# Paper and Fiber-Based Bio-Diagnostic Platforms: Current Challenges and Future Needs
## 1 Introduction
\begin{table}
\begin{tabular}{|c|p{142.3 pt} p{142.3 pt} p{142.3 pt}|p{142.3 pt}|} \hline
**Paper/riber** & **Strategies** & **Advantages** & **Disadvantages** & **Ref.** \\ \hline
**PHB** & & Higher sensitivity and specificity than the conventional method without needing surface treatments & The need to remove the papers from the well plate for final readout makes the platform & **[3]** \\  & & Integrated into 96-well plate for dengue surface treatments & surface treatments & less efficient & \\ \hline
**PHBV** & & Customized fiber material with tailored surface properties, tuned wettability and morphological characteristics & Presence of double-sided adhesive layer might & **[6]** \\ \hline
**Nylon** & Polymer/copolymer dip-coated nylon embedded into 96-well plate for dengue virus detection & Reasonable price, favorable chemistry of the surface without needing surface treatments & Low stability of the coated nylon membrane in the assay & **[37]** \\ \hline
**Cellulose** & Photolithography technique was applied to fabricate paper-based 96-well plate for detection of HIV-1 & Offers a rapid analysis that requires small volumes of samples and reagents, and utilizes simple equipment & The technique is less sensitive than conventional ELISA by approximately one order of magnitude & **[66]** \\ \hline
**Whatman \# 42** & Paper-based disk for detection of T7 bacteriophage & Complete with the sophisticated laboratory & The sensitivity is comparable to the diagnostic techniques applied for bio-recognition of pathogenic viruses and other microorganisms & **[67]** \\ \hline
**Fusion 5 TM** & Paper-based ELISA for _E. coli_ detection & Rapid, low cost (-51 per prototype), short training time, and minimal medical waste & Detection was only performed for _E. coli_ sample within the laboratory, while further clinical validation is required & **[68, 69]** \\ \hline
**Nitocellulose** & & Wax printing technique was applied to fabricate a pAD equipped with timing valves for imidclopid detection & Equipped with timing valve that provides an opportunity for multiple-step performance in assay procedure & **[70]** \\ \hline
**Nitocellulose** & & Listed printing technique was applied to fabricate a pAD equipped with timing valves for hCG detection & Simple, straightforward, and low cost fabrication technique by using higher printing & There is a chance for error and over estimation of the sensitivity & **[71]** \\ \hline \end{tabular}
\end{table} 
Table 3: _Cont._When actual clinical practice is concerned, a small percentage of these techniques open a way for translation from the laboratory bench to the hands of the final users and thus patient care. Even though the currently applied fabrication strategies are promising and the developed prototypes possess tremendous value, further efforts should be dedicated to overcoming the existing limitations. By opening a wide perspective into the bio-sensing domain, the application of papers and fibers has produced an obvious and important shift in the healthcare paradigm. However, several of the developed platforms suffer from a critical lack of reproducibility and limited detection options, as well as insufficient level of sensitivity [4; 76]. In this perspective article, some of the principal challenges of the developed strategies and the opportunities for future development targets are discussed.