# Collagen Nanoparticles in Drug Delivery Systems and Tissue Engineering
## 3 Collagen-Based NPs in Biomedicine
### Collagen Based NPs in TE  
Gold NPs were incorporated into collagen nanoparticle scaffolds which later on reacted with growth factors and molecules for cell adhesion. This helped in reduction of inflammation and formation of granulation tissue with no problems of rejection, which make them perfect for wound healing [32]. [PERSON] et al. conducted experiments which displayed that gold NPs along with cryopreserved human fibroblasts administered top \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Agent (Crosslinking/Stabilising/Optimising)** & **Effect of Collagen NPs** & **Application** & **Reference** \\ \hline Malondialdehydedehyde(MDA); 3-ethyl & Enhanced bioavailability and improved & Drug for Neuronal injury & [69] \\ carbodiimide-hydrochloride (EDC-Hcl) & therapeutic effect of silymarin drug & Drug delivery to the brain & [70] \\ \hline  & Enables identification of the particular cell & Drug delivery to the brain & [70] \\  & surface receptors which allows transcytosis & & \\ \hline  & Enhancement of motor functions in PD model & Nerve Growth Factor (NGF) & \\  & and cognitive functions in AD model & delivered to the brain & [73] \\ \hline Gold NPs (Au) on & Enhanced Au-HAp-Col NPs with bioactive and & Drug delivery, scaffold & \\ hydroxyapatite (HAp) surface & biocompatible characteristics for loading and & materials, cell growth, & \\  & releasing of the doxorubicin drug & proliferation and adhesion & \\ \hline Silver NPs (DdAgNPs) with & Stronger antibacterial action against all the test & & \\ doxycycline (DO) & organisms compared to the DdAgNPs alone & & \\ \hline
95-D, U87 and HCT116 cells & More precise therapeutic results and dynamics & Tumor infiltration for & \\  & of the drug transport agents in vivo & anti-cancer drug delivery & [77] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Investigations on collagen NPs in DDS. ically to burns and wounds increased the rate of healing and enhanced collagen deposition [32; 78]. [PERSON] et al. fabricated scaffolds based on silver, pectin and collagen NPs which supplied greater antibacterial activity and improved viability of the cell toward keratinocytes [79]. [PERSON] et al. prepared scaffolds of silver and collagen NPs for burn and wound healing, and skin repair. Hydroxyapatite silver collagen nanoparticle composite scaffolds acted as prospective bone graft materials [80; 81]. [PERSON] et al. developed a construct of collagen NPs for TE applications and imaging by crosslinking \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) NPs capped with starch to collagen. This construct had enhanced mechanical properties, had better crosslinking, was able to provide better viability to the cell, had greater super paramagnetic behaviour and could be used in imaging and as bio implants [82; 83]. [PERSON] et al. prepared tissue constructs based on skeletal muscles with acellular tissue scaffolds based on collagen NPs which enhanced contractile force generation [80; 84]. [PERSON] et al. studied the production of collagen nanoparticle bone and development for preservation of alveolar ridge. For protection of the residual ridge after extraction of the tooth, artificial collagen nanoparticle bone was introduced into the patient. Scans taken showed that the residual ridge had combined with the collagen nanoparticle bone which also had a greater alveolar bone mineral density [35; 85]. [PERSON] et al., after trials on rabbits, displayed enhanced rate of solid fusion and bone mineral density when bone based on collagen NPs along with stem cells derived from adipose and allogeneic was utilized. They could also be used to repair defects in the human ulna [86]. [PERSON] et al. prepared porous scaffolds using collagen glycosaminoglycan (CG) and bioactive glass to promote TE in the bone [87; 88]. Collagen and hydroxyapatite could be manufactured to form a composite of collagen-hydroxyapatite by lyophilization and dehydrothornethreatment [89; 90].