Abstract:
The present disclosure relates to a tissue collection apparatus. The tissue collection apparatus comprises a housing defining an inlet and an outlet, a first filter disposed within the housing, a second filter disposed within the housing, the second filter configured to isolate tissue particles of a desired size that pass through the first filter under the application of an aspiration force applied through the housing. A method of harvesting tissue is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Patent Application No. 60/909,253 filed on Mar. 30, 2007, U.S. Patent Application No. 60/992,210 filed on Dec. 4, 2007, U.S. Patent Application No. 61/006,662 filed on Jan. 25, 2008, U.S. Patent Application No. 61/006,663 filed on Jan. 25, 2008, and UK Provisional Patent Application 0715429.7 filed on Aug. 8, 2007, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to tissue harvesting. 
     BACKGROUND 
     Articular cartilage lines the ends of bones and facilitates frictionless movement of joints. Damage to the cartilage caused by injury or disease does not heal and the pathological changes resulting from this damage can be a source of great pain; limiting mobility and having a significant detrimental impact on the quality of life. Over time, lesions are likely to degenerate into osteoarthritis. Injury is not the only cause of osteoarthritis, with genetics, obesity, joint biomechanics, diet and age all playing a role. 
     Known surgical techniques for treating damaged cartilage comprise lavage and debridement (joint is flushed with fluid and damaged tissue removed providing temporary symptom relief); microfracture (penetration of the subchondral bone to stimulate bleeding in to the cartilage lesion in an effort to promote a fibrocartilage healing response); periosteal grafts (autologous periosteum is grafted into the defect site and sutured or glued into place); mosaicplasty (plugs of cartilage and bone are harvested from low weight bearing regions of the joint and transplanted into the defect); and autologous chondrocyte implantation (ACI) (cells are isolated and expanded from a cartilage biopsy from a non-weight bearing location, and the cells are re-introduced into the defect in a second procedure approximately six weeks later either in suspension or on a scaffold (Matrix-guided ACI-MACI)). 
     SUMMARY 
     The tissue harvesting techniques described below can be used to repair, regenerate, and/or augment tissue in a range of surgical or cosmetic applications. 
     Trauma to the articular surface is a common injury in sports. The symptoms arising from such damage comprise pain, joint locking, instability, and stiffness, and the damage predisposes the cartilage and joint to wear and degeneration which can lead to osteoarthritis and the need for total knee replacement. For example, the tissue harvesting techniques can be used to treat focal and degenerative cartilage lesions before a total joint replacement is indicated and can postpone or obviate the need for a total joint replacement. The techniques enable the surgical team to purify a unique population of repair cells from tissue from the patient, such as, for example, synovial/adipose tissue, and deliver the cells back into the patient&#39;s joint to stimulate a hyaline-like cartilage repair in a single surgical procedure. The repair cells are harvested arthroscopically from a site local to the defect (i.e. within the joint), the repair cells of a desired range are isolated, for example, by filtering, and the isolated cells are mixed in an unprocessed state (e.g., without further culturing, concentrating, etc.) with a biocompatible gel. The mixture of gel and the isolated harvested cells is then provided to the repair site. 
     In implementations of the disclosure the adipose tissue harvested is a fat pad or corpus adiposum, which is a localised accumulation of encapsulated adipose tissue. Fat pads can be found, for example in the cheek (corpus adiposum buccae) and also found within certain joints where they are referred to as the infrapatellar, navicular, olecranon, scaphoid, pronator quadratus, and preachilles fat pads. These pads may act as a cushion to absorb forces generated across the joint and also may help to distribute lubricants in the joint cavity. 
     The infrapatellar fat pad, also referred to as Hoffa&#39;s pad and adipose synovium, comprises synovium and subsynovial adipose tissues and lies beneath the patella (kneecap) separating it from the femoral condyle. The infrapatellar fat pad varies in size and volume, but generally comprises two large basal prominences lying on either side of the intrachondylar notch. In situations where forces are directed at the patella, the infrapatellar fat pad acts as a shock absorber, protecting the underlying structures. During trauma the infrapatellar fat pad undergoes a number of changes, which comprise, without limitation, the fat pad volume increasing secondary to oedema and haemorrhage due to increased subsynovial vascularisation and the subsequent infiltration of the fat pad with macrophages. 
     We have found that by harvesting a defined size fragment of fat pad tissue, comprising progenitor cells, and reintroducing this fragment in combination with a biocompatible scaffold, such as a gel, into another site within the body, it is possible to generate tissue types that are different from the tissue fragment following exposure of the fragment to environmental factors. 
     It is envisaged that the progenitor cells contained within the fragments of fat pad could be directed along, for instance, the osteogenic, adipogenic, chondrogenic, myogenic, neurogenic lineages giving rise to bone, cartilage, muscle or nerve tissue. 
     Once the fat pad fragments are implanted into the site, the progenitor cells migrate out of the fragments and integrate into the surrounding tissue, thereby allowing the progenitor cells to differentiate into the appropriate endogenous cell type(s). 
     The fat pad tissue can be autogeneic tissue, allogeneic tissue, xenogeneic tissue and combinations thereof. 
     The use of autogeneic tissue is particularly desirable as it substantially reduces the potential for an immunogenic host response and tissue rejection. 
     If autogenic fat pad is to be used, a specific consideration for the surgeon is how readily accessible the fat pad is during the primary surgical procedure. For example, if a surgeon is repairing a cartilage defect within the femoral plateau, then it would be appropriate to use the infrapatellar fat pad. This will minimise the incisions that the surgeon has to make and therefore improve the outcome and the welfare of patient. 
     Using autologous tissue as a source for cartilage repair implants is often limited due to a number of problems including: availability, source, pain and enrichment. The infrapatellar fat pad is a joint tissue that is easily accessible to the orthopedic surgeon and is present in sufficient quantity to load a number of scaffolds for use in cartilage repair, particularly of focal defects. Furthermore, the use of the infrapatellar fat pad substantially reduces the possibility of secondary site morbidity when compared to other tissue sources, such as bone marrow aspirations, and substantially reduces the need to enrich the progenitor cells to show therapeutic effect. 
     In one aspect, the present disclosure relates to an apparatus for tissue collection comprising:
         a housing defining an inlet and an outlet;   a first filter disposed within the housing;   a second filter disposed within the housing, the second filter configured to isolate tissue particles of a desired size that pass through the first filter under the application of an aspiration force applied through the housing.       

     Implementations may comprise one or more of the following features. For example, the apparatus further comprises a third filter disposed in the housing between the first and second filters. The second filter is configured to isolate tissue particles of a desired size that pass through the first and third filters under the application of the aspiration force applied through the housing. The first and second filters disposed within the housing define an interior space within the housing, wherein the apparatus further comprises a port disposed within the housing and in fluid-flow communication with the interior space defined within the housing. The apparatus further comprises an introducer configured to comprise a gel. The introducer is configured to be coupled to the outlet of the housing to introduce the gel into the interior space of the housing, such that in use, the gel passes through the second filter and removes isolated tissue particles collected on the second filter, and wherein the gel and isolated tissue particles collect in the interior space of the housing. The apparatus further comprises a mixer and a receiver. The mixer and the receiver are configured to be releasably coupled to the port to receive the gel and isolated tissue particles from the interior space of the housing. The first filter comprises a set of pores having a pore size of about 0.6 mm to about 2.4 mm, the second filter comprises a set of pores having a pore size of about 0.5 mm to about 50 μm, and the third filter comprises a set of pores having a pore size of about 0.6 mm to about 1 mm. The apparatus further comprises a fluid-flow conduit in the interior space of the housing and in fluid-flow communication with the inlet and the outlet. The apparatus further comprises a second port disposed in the housing. The first port and the second port are in fluid-flow communication with the conduit. The apparatus further comprises a first valve and a second valve, the first and second valves configured to allow for selective control of fluid flow between the inlet and the outlet and the first and second ports. The inlet is in fluid communication with a surgical blade and the outlet is in fluid communication with an aspiration source. 
     In an embodiment, the housing comprises a removable lid. The first filter is disposed within the lid. The third filter is disposed within the lid between the first filter and the second filter. The second filter comprises a basket mesh or a substantially frusto-conical configuration. The second filter is releasably coupled to the housing or the lid. The apparatus further comprises a container shaped to receive the second filter therein upon removal of the second filter from the housing. 
     In another aspect, the present disclosure relates to a method of harvesting tissue comprising isolating particles of a desired range from cut tissue aspirated through a tissue cutter, mixing the isolated particles in an unprocessed state with a biocompatible gel, and collecting the mixed particles and gel in an introducer for implantation into a surgical site. 
     Implementations may comprise one or more of the following features. For example, isolating the particles of a desired range comprises passing the cut tissue through a first filter and a second filter. The second filter comprises openings sized to permit collection of the particles of the desired range on the second filter. The method further comprises passing the biocompatible gel through the second filter to remove isolated particles collected on the second filter prior to mixing the isolated particles with the biocompatible gel. Mixing the isolated particles and the gel comprises passing the isolated particles and gel through a mixer coupled to the introducer Mixing the isolated particles and the gel also comprises placing the second filter with the collected particles in a container configured to receive the second filter therein and introducing the biocompatible gel into the container. The collecting step comprises aspirating the mixed isolated particles and the gel from the container into the introducer. The cut tissue is synovial or adipose tissue. The isolating step comprises collecting particles of the desired range in a filter of a tissue collection device solely under the application of an aspiration force applied through the tissue collection device to the aspiration lumen of the tissue cutter to aspirate tissue therethrough. 
     Advantages may comprise eliminating the risk of disease transmission and immune response associated with treatment using allograft; enabling cartilage repair procedures to be performed in focal lesions in older as well as young patients; minimizing damage to the donor site; isolating tissue fragments which are within a specific size range; minimizing intervention from the surgeon; and harvesting tissue, loading tissue within a gel in an expedient manner, and providing the tissue-containing gel for tissue repair in a sterile manner in a single surgical procedure. 
     The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is an illustration of a tissue harvesting assembly shown in use. 
         FIG. 2  is a cross-sectional view of the surgical blade hub of the assembly of  FIG. 1 . 
         FIG. 3  is a perspective view of a tissue collection apparatus of the assembly of  FIG. 1 . 
         FIGS. 4   a - 4   d  schematically illustrate use of the tissue collection apparatus of  FIG. 3  to isolate tissue particles of a desired size and to prepare a mixture of tissue-containing gel for tissue repair. 
         FIG. 5  is an illustration of an alternative tissue harvesting assembly shown in use. 
         FIG. 6  is a cross-sectional view of a tissue collection apparatus of the assembly of  FIG. 5 . 
         FIGS. 7   a - 7   f  schematically illustrate use of the tissue collection apparatus of  FIG. 6  to isolate tissue particles of a desired size and to prepare a mixture of tissue-containing gel for tissue repair. 
         FIG. 8  is an illustration of an alternative implementation of the tissue collection apparatus of the assembly of  FIG. 1 . 
         FIG. 9  is a cross-section view of the tissue collection apparatus of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a tissue harvesting assembly  100  comprises a surgical blade  10  used to cut or resect bodily tissue T, such as synovial or adipose tissue, from a donor site, coupled to a tissue collection device  40  for isolating cut tissue of a desired size aspirated through the surgical blade  10 . As discussed below, during the same surgical procedure, the isolated cut tissue is loaded into, or mixed with, an appropriate carrier, such as a biocompatible gel, and introduced at a tissue repair site. Preferably, the donor site and the repair site are within the same joint to minimize trauma to the patient and provide for a more expedient surgical procedure. 
     Surgical blade  10  uses a tube-in-tube construction to shear tissue disposed between cutting edges of an elongate outer non-rotating tubular member  12  and an elongate inner rotating tubular member  14 , as more fully explained in U.S. Pat. No. 5,871,493, which is incorporated herein by reference in its entirety. The surgical blade  10  comprises a handpiece  20  coupled to the tubular members  12 ,  14  via a hub  22 . The outer tubular member  12  has a proximal end  12   a  fixed to the hub  22  and a distal end  12   b  defining an opening  15  forming a cutting port or window. The inner tubular member  14  is rotatably received in the outer tubular member  12  and has a distal end  14   a  with a cutting edge (not shown). The inner tubular member  14  defines an aspiration lumen  16  ( FIG. 2 ) communicating with the cutting edge to remove cut tissue and fluid from a surgical site. When the blade  10  is assembled, the cutting edge of the inner tubular member  14  is positioned adjacent the opening  15  of the outer tubular member  12 . 
     Referring to  FIG. 2 , the hub  22  ( FIG. 1 ) of the surgical blade  10  is coupled to the outer tubular member  12  via an opening  41  formed in the hub  22 . The inner tubular member  14  is rotatably received within the outer tubular member  12  and defines the aspiration lumen  16  extending longitudinally through the inner tubular member  14 . The inner tubular member  14  further defines one or more openings  45  formed through a side wall  14   b  of the member  14  within the hub region of the blade  10 , which are in fluid communication with the aspiration lumen  16  and a chamber  26  defined within hub  22 . Hub  22  further comprises a side port  24  formed through a side wall  28  of hub  22  and in fluid communication with the chamber  26 . The side port  24  extends in a direction substantially transverse to the longitudinal axis L of the inner tubular member  14 . Coupled to the side port  24  is a tubing connector  29 . The side port  24  provides a pathway for fluid and cut tissue to flow from the surgical blade  10  to the tissue collection device  40 . 
     Referring to  FIGS. 1 ,  3 , and  4 A- 4 D, in addition to the tissue collection device  40 , the tissue harvesting assembly  100  comprises an introducer  60  ( FIGS. 4B-4D ) and a mixer  65  ( FIGS. 4B-4D ). The tissue collection device  40  is coupled to the blade  10  via a flexible tubing  50 . The tissue collection device  40  comprises a substantially cylindrical housing  42  having an inlet  44  and an outlet  46 . The inlet  44  couples the tubing  50  to the tissue collection device  40 . The outlet  46  is provided to couple the tissue collection device  40  to a source of vacuum  90  ( FIG. 1 ), such as a vacuum pump or other suitable apparatus for providing aspiration during the surgical procedure, via a tubing  52 . In addition, a collection apparatus (not shown) can be coupled to the tissue collection device  40  via the tubing  52  to collect tissue and fluid that passes through the tissue collection device  40 . 
     Filtration devices, such as disc filters  47 ,  48 , and  49 , are positioned within the housing  42  with filter  47  disposed closest to or adjacent the inlet  44 , filter  49  disposed closest to or adjacent the outlet  46 , and filter  48  disposed between filters  47  and  49 . The filters  47 ,  48 , and  49  and the housing  42  cooperate to define an interior space  41  within the housing  42 . The housing  42  comprises a port  45  disposed therein, which is in fluid-flow communication with the interior space  41  of the housing  42 . 
     In the implementation shown in  FIGS. 1 ,  3 , and  4 A- 4 D, the filter  47  comprises a set of pores having a pore size of about 0.6 mm to about 2.4 mm, the filter  48  comprises a set of pores having a pore size of about 0.6 mm to about 1 mm, and the filter  49  comprises a set of pores having a pore size of about 0.5 mm to about 50 μm. The filters  47  and  48  filter out larger tissue particles and allow smaller particles to pass through. The filter  49  then filters out particles  71  ( FIG. 4B ) of a desired size and allow particles smaller than the desired size to pass through. While two filters  47 ,  48  are shown in this implementation, the tissue collection device  40  may comprise only one of the filters  47 ,  48  used in conjunction with the filter  49  to collect tissue particles  71  of a desired size. 
     The introducer  60  ( FIGS. 4B-4D ), for example, a syringe, contains a suitable volume (e.g., about 1 ml) of a biocompatible gel  62 . After particle collection, the syringe  60  is used to inject the biocompatible gel  62  into the housing  42  to allow the recovery of the tissue particles  71  collected by the filter  49  as will be discussed in more detail below. The mixer  65  ( FIGS. 4B-4D ), such as a static mixer, is releasably coupled to the port  45  to receive the gel  62  and isolated tissue particles  71  from the interior space  41  of the housing and to create a mixture  80  of gel  62  and tissue particles  71 . A receiver  70  ( FIGS. 4B-4D ) is releasably coupled to the mixer  65  to receive the mixture  80  from the mixer  65  and to, for example, provide the mixture  80  to a surgical site. 
     In operation, as shown in FIGS.  1  and  4 A- 4 D, the surgical blade  10  is brought into contact with a desired bodily tissue, such as synovial or adipose tissue ( FIG. 1 ). The operator cuts a desired amount of tissue from the donor site using the blade  10 . The vacuum source  90  aspirates fluid and the cut tissue through the aspiration lumen  16  of the inner tubular member  14  to the tissue collection device  40 . During aspiration of the fluid and cut tissue, the port  45  in the housing  42  is closed ( FIG. 4A ), using, for example, a valve, stop, plug, or other suitable device  43 . The filter  47  removes undesirable cut tissue from the fluid pathway, such as particles larger than, for example, about 0.6 mm to about 2.4 mm. After passing through the filter  47 , the remainder of the fluid and cut tissue pass through the filter  48 , which removes undesirable cut tissue from the fluid pathway, such as particles larger than, for example, about 0.6 mm to about 1 mm. The remainder of the fluid and cut tissue pass through the filter  49  where tissue particles  71  of a desired size, such as particles larger than, for example, about 0.5 mm to about 50 μm are isolated and/or retained on the filter  49 . The remainder of the cut tissue and fluid volume pass through the tissue collection device  40  and are aspirated to the collection apparatus (not shown). 
     Following aspiration of the fluid and cut tissue, the inlet  44  of the housing  42  is closed off using, for example, a valve, stop, plug, or other suitable device  43   a , the housing  40  is removed from the tubing  50 ,  52 , and the receiver  70  and static mixer  65  are attached to the port  45 , using, for example, a Luer Lock (not shown) or other suitable connector ( FIG. 4B ). The syringe  60  containing the gel  62  is coupled to the outlet  46 , for example, by a Luer lock (not shown) or other suitable connection. The gel  62  is then injected into the housing  40  and through the filter  49  to mix with and expel the tissue particles  71  from the filter  49  ( FIG. 4C ). The expelled tissue particles  71  and the gel  62  pass through the interior space  41  of the housing  42  and are forced through the port  45  to the mixer  65  ( FIG. 4C ). The mixer  65  mixes the tissue particles  71  and the gel  62  to promote even distribution of the tissue particles  71  within the gel  62 , creating a mixture  80 , which flows into the syringe  70  ( FIGS. 4C-4D ). Once the desired volume of the mixture  80  is collected in the syringe  70 , the operator removes the syringe  70  from the mixer  65  and attaches the plunger  70   a  of the syringe  70  ( FIGS. 4   c - d ). The operator then applies the mixture  80  at a desired location, such as the surgical site shown in  FIG. 1 , or the mixture  80  can be placed onto a tissue scaffold or used for further processing. 
     An alternative implementation of a tissue harvesting assembly  200  is illustrated in  FIGS. 5 ,  6 , and  7 A- 7 F. The tissue harvesting assembly  200  comprises a tissue collection device  140  and an introducer  160  ( FIGS. 7E-7F ), for example, a syringe, containing a suitable volume (e.g., about 1 ml) of gel  62 . The tissue collection device  140  comprises a substantially cylindrical housing  142  having an inlet  44  and an outlet  46 . The housing  142  comprises a lid  143  that is releasably coupled to the housing  142  using, for example mating threads (not shown), a friction fit, or other suitable connection. 
     Filtration devices, such as disc filters  147 ,  148  and a filter  149  having a substantially frusto-conical or basket configuration, are positioned within the housing  142 , with filter  147  disposed closest to or adjacent the inlet  44 , filter  149  disposed closest to or adjacent the outlet  46 , and filter  148  disposed between filters  147  and  149 . In particular, the filters  147 ,  148  are disposed within the lid  143 , and the filter  149  is removably attached to an underside  143   a  of the lid  143 , using, for example, threads (not shown), a friction fit, or other suitable connection. The housing  140  comprises one or more projecting ribs  145  ( FIG. 6 ) disposed about the interior of the cylindrical housing  140 . The ribs  145  are configured and shaped to receive the filter  149  and to releasably hold the filter  149 , for example, by a friction fit, within the housing  140 . 
     The filter  147  comprises a set of pores having a pore size of about 0.6 mm to about 2.4 mm, the filter  148  comprises a set of pores having a pore size of about 0.6 mm to about 1 mm, and the filter  149  comprises a set of pores having a pore size of about 0.5 mm to about 50 μm. The filters  147  and  148  filter out larger tissue particles and allow smaller particles to pass through. The filter  149  then filters out particles  71  ( FIG. 7B ) of a desired size and allow particles smaller than the desired size to pass through. While two filters  147 ,  148  are shown, the tissue collection device  140  may comprise only one of the filters  147 ,  148  used in conjunction with the filter  149  to collect tissue particles  71  of a desired size. 
     The assembly  200  further comprises a container  170  defining a cavity  170   a  ( FIGS. 7C-7F ) configured and shaped to receive the filter  149  in a fluid-tight manner therein. An upper portion  170   b  of the container  170  is configured with threads, or other suitable mating connections, to receive the lid  143  of the housing  140  as will be described in more detail below. 
     The introducer  160  ( FIGS. 7E-7F ), for example, a syringe, contains a suitable volume (e.g., about 1 ml) of gel  62 . The syringe  160  is used to mix the gel  62  with the tissue particles  71  to create a mixture  80  within the container  170 , and thereafter, to aspirate the mixture  80  from the container  170 . 
     In operation, as shown in FIGS.  5  and  7 A- 7 F, the surgical blade  10  is brought into contact with a desired bodily tissue, such as synovial or adipose tissue ( FIG. 5 ). The operator cuts a desired amount of tissue from the donor site using the blade  10 . The vacuum source  90  aspirates fluid and the cut tissue through the aspiration lumen  16  of the inner tubular member  14  to the tissue collection device  140 . During aspiration, the fluid and cut tissue flow through the filter  147 , which removes undesirable cut tissue from the fluid pathway, such as particles larger than, for example, about 0.6 mm to about 2.4 mm. After passing through the filter  147 , the remainder of the fluid and cut tissue pass through the filter  148 , which removes undesirable cut tissue from the fluid pathway, such as particles larger than, for example, about 0.6 mm to about 1 mm. The remainder of the fluid and cut tissue pass through the filter  149  where tissue particles  71  ( FIG. 7B ) of a desired size, such as particles larger than, for example, about 0.5 mm to about 50 μm are isolated and/or retained on the filter  149 . The remainder of the cut tissue and fluid volume pass through the tissue collection device  140  and are aspirated to the collection apparatus (not shown). 
     Following aspiration of the fluid and cut tissue, the lid  143 , including the filters  147 ,  148 , and  149 , is removed from the housing  142  ( FIG. 7B ) and coupled to the upper portion  170   b  of the container  170  ( FIG. 7C-7D ). The cavity  170   a  receives the filter  149  in a fluid-tight manner, via, for example, a friction fit, between the filter  149  and the cavity  170   a . Once the filter  149  is positioned in the container  170 , the operator removes the lid  143 , including the filters  147 ,  148 , from the container  170 , leaving the filter  149  within the cavity  170   a  of the container  170 . For example, if the filter  149  is coupled to the lid  143 , using a threaded connection and the lid  143  is coupled to the container  170  via a threaded connection, the two sets of threaded connections may be configured such that when the lid  143  is unscrewed from the container  170 , the filter  149  is unscrewed from the lid  143 . Alternatively, if, for example, the filter  149  is coupled to the lid  143  via a friction fit, then the cavity  170   a  of the container  170  is configured to provide a sufficient force to retain the filter  149  upon removal of the lid  143  from the container. 
     Once the lid  143  is removed from the container  170 , the operator uses the syringe  160  to inject the gel  62  within the cavity  170   a . The gel  62  mixes with the tissue particles  71  to form a mixture  80  of tissue and gel ( FIG. 7E ). The mixture  80  is then aspirated from the container  170  using the syringe  160  ( FIG. 7F ). Once the desired volume of the mixture  80  is collected in the syringe  160 , the operator may apply the mixture  80  at a desired location, such as the surgical site shown in  FIG. 5 , or the mixture  80  can be placed onto a tissue scaffold or used as a feed for further processing. 
     In an alternative implementation illustrated in  FIGS. 8 and 9 , a tissue collection device  240  comprises a housing  242  having an inlet  244  and an outlet  246 . Positioned within the housing  242  are filters  247  and  249 . Filter  247  is disposed adjacent the inlet  244  and filter  249  is disposed adjacent the outlet  246 . Extending between the inlet  244  and the outlet  246  is a fluid-flow conduit  250  in fluid-flow communication with the inlet  244 , the outlet  246  and the filters  247  and  249 . The housing  242  further comprises ports  252  and  254  in fluid-flow communication with the conduit  250  via conduits  252   a  and  254   a , respectively. At the intersections of conduits  250  and  252   a  and conduits  250  and  254   a  are three-way valves  256 ,  258 , respectively, that control flow of fluid and tissue or cells between the inlet  244  and the outlet  246 , and flow of gel and a mixture of gel and tissue or cells between the ports  252  and  254 , as will be described in more detail below. 
     In the implementation shown in  FIGS. 8 and 9 , the filter  247  comprises a set of pores having a pore size in the range of about 0.6 mm to about 2.4 mm to allow particles smaller than the pore sizes to pass through the filter  247  and the filter  249  comprises a set of pores having a pore size of about 50 μm to about 0.5 mm to capture particles larger than about 50 μm in the filter  249 . 
     In operation, the operator cuts a desired amount of tissue from a donor site using the surgical blade  10 , as described above, and fluid and cut tissue are aspirated through the tissue collection device  240  via the inlet  244 . During aspiration of the fluid and cut tissue, the ports  252  and  254  are closed to fluid flow by the three-way valves  256  and  258 . The filter  247  removes undesirable cut tissue from the fluid pathway, such as particles in the range of larger than about 0.6 mm to about 2.4 mm. After passing through the filter  247 , the fluid and cut tissue pass through the conduit  250  and through the filter  249  where tissue particles of a desired size, such as particles larger than, for example, about 0.5 mm to about 50 μm are isolated and/or retained on the filter  249 . The remainder of the cut tissue and fluid volume pass through the tissue collection device  240  and are aspirated to a collection apparatus (not shown). 
     Following aspiration of the fluid and cut tissue, the inlet  244  of the housing  242  is closed off to fluid flow and the port  252  is opened to fluid flow using, for example, three-way valve  256 . Likewise, the outlet  246  of the housing  242  is closed off to fluid flow and the port  254  is opened to fluid flow using, for example, three-way valve  258 . The receiver  70 , and optionally, the static mixer  65 , discussed above, can then be attached to the port  252 . The syringe  60  containing the gel  62  is then coupled to the port  254  and the gel  62  is injected into the housing  240  and through the filter  249  to mix with and expel the tissue particles (not shown) from the filter  249 . The expelled tissue particles and gel  62  pass through the conduit  250  and are forced through the port  252  to, for example, the mixer  65  ( FIG. 4C ) and into the receiver  70  as described above. 
     In addition to being used in conjunction with the surgical blade assemblies described above, each of the tissue collection devices  40 ,  140 , and  240  can be loaded with biological components by other methods. For example, cell pellets cultured in vitro can be aspirated (e.g. using a vacuum source) through one of the tissue collection devices  40 ,  140 ,  240  and then mixed with a biocompatible gel in the manner described above. 
     A number of implementations of the disclosure have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, while the tissue collection devices  40 ,  140 ,  240  have been described as coupled to the blade  10  via a flexible tubing  50 , the devices  40 ,  140 ,  240  could be directly coupled to, for example, the port  24  of the blade  10  (see  FIGS. 1 and 5 ). In addition, although the tissue collection devices  40 ,  140 ,  240  have been described as including substantially cylindrical housings  42 ,  142 , and  242 , respectively, housings  42 ,  142 , and  242  could be any suitable shape. Further, although the syringes  60 ,  160  have been described as containing a volume of about 1 ml of a biocompatible gel  62 , the syringes  60 ,  160  could contain more or less of the gel  62  depending on the size of the defect to be treated. 
     In addition, rather than using a static mixer with the tissue collection device  40  to promote a more even distribution of the tissue particles  71  in the gel  62 , the mixture  80  of gel  62  and tissue particles  71  may be realized solely within the interior space  41  of the housing  42 , and the syringe  70  can be directly coupled to the port  45  to recover the mixture  80  directly from the interior space  41  of the housing  42 . Further, rather than mixing the gel and tissue in a separate container, such as container  170 , the outlet  46  of the tissue collection device  140  can be plugged or otherwise sealed and the mixture  80  of gel  62  and tissue particles  71  can be realized directly in the tissue collective device  140 . 
     Moreover, although the filtration devices have been described as either disk-shaped or basket-shaped filters, other suitable filtration devices having any number of possible geometric shapes may be employed. Such examples comprise nucleated cell, microfiltration, tubular, or hollow fiber filtration devices, having, for example, square, cylindrical, tubular, or round geometries. In addition, any filtration surface that contacts any of the relevant compositions of the tissue, fluid, or other surgical materials is sterile or can be readily sterilized. 
     For the purposes of this disclosure, the injectable gel  62  may comprise any suitable biological or synthetic gels. For example, the gel can comprise hyaluronic acid, alginate, cross-linked alginate, collagen, fibrin glue, fibrin clot, poly(N-isopropulacrylamide), agarose, chitin, chitosan, cellulose, polysaccharides, poly(oxyalkylene), a copolymer of poly(ethylene oxide)-poly(propylene oxide), poly(vinyl alcohol), polyacrylate, Matrigel, or blends thereof. 
     The apparatuses and systems described herein may be considered disposable, although they may be reused upon sterilization, such as by gamma irradiation, ethylene oxide, formalin, hydrogen peroxide, or sodium hypochlorite. The filters and syringes discussed herein may be commercially obtained. In particular implementations, the apparatus and components may be plastic, metal, or other suitable material. 
     Rather than the tubing connector  29  ( FIG. 2 ) being in communication with the aspiration lumen  16  of the inner tubular member  14  via the chamber  26 , the tubing connector  29  could be directly coupled to the inner tubular member  14 . The tubing connector  29  can be coupled to the side port  24  using any suitable form of connection, including glue, weld, press fit, or, alternatively, the tubing connector  29  can be formed as one piece with the hub  22 . The tubing connectors described herein can be made from plastic, metal, or any other suitable materials. 
     In addition, although the tissue harvesting assembly has been described as including a surgical blade  10  used to cut or resect bodily tissue, such as soft tissue, the tissue harvesting assembly can comprise an apparatus containing a curet or burr, for example, to remove bodily tissue, such as bone tissue. 
     Accordingly, other embodiments are within the scope of the following claims.