Direct Observation of Adhesion and Mechanical Behavior of a Single Poly(lactic-co-glycolic acid) (PLGA) Fiber Using an In Situ Technique for Tissue Engineering

Abstract

Nanometer- and submicrometer-sized fiber have been used as scaffolds for tissue engineering, because of their fundamental load-bearing properties in synergy with mechano-transduction. This study investigates a single biodegradable poly­(lactic-co-glycolic acid) (PLGA) fiber’s load–displacement behavior utilizing the nanoindentation technique coupled with a high-resolution in situ imaging system. It is demonstrated that a maximum force of ∼3 μN in the radial direction and displacement of at least 150% of fiber diameter should be applied to acquire the fiber’s macroscopic mechanical properties for tissue engineering. The adhesion behavior of a single fiber is captured using a high-resolution camera. The digital image correlation (DIC) technique is adopted to quantify the adhesion force (∼25 μN) between the fiber and the tip. Adhesion force has also been quantified for the fiber after immersing in phosphate-buffered saline (PBS) to mimic the bioenvironment. A 4-fold increase in adhesion force after PBS treatment was observed due to water penetration and hydrolysis on the fiber’s surface. A high similarity between mechanical properties of a single fiber and native tissues (elastic modulus of 10–25 kPa) and superior adhesion force (25–107.25 μN) was observed, which is excellent for promoting cell-matrix communication. Overall, this study examines the mechanics of a single fiber using innovative indentation and imaging processing techniques, disclosing its profound and striking roles in tissue engineering.

Modification of nanofibrous scaffolds to mimic extracellular matrix in physical and chemical structuring

“…[1,2] In addition to structural similarity to natural ECM, the electrospun fibers offer many advantages, such as their feasibility in controlling diameter ranging from nanoscale to microscale and natural porous structure. [3,4] Varied synthesized polymers, such as thermoplastic polyurethane, polycaprolactone (PCL), [5,6] poly(lactide-co-glycolide) (PLGA), [7,8] and poly(lactic acid) (PLA), [9,10] have been successfully electrospun into nanofibers with adjustable mechanical properties. However, the synthetic polymers always lack cell recognition sites and the hydrophilicity of the prepared scaffolds is usually very poor, which are very unfavorable for cell growth.…”

Localized Nanoindentation Paradigm for Revealing Sutured Tissue Interface Mechanics and Integrity

“…A suture yarn size of 4−0 (or 3−0) can contribute to an optimal wound healing speed when subjected to abdominal trauma, 19 which was selected in this study. 20 evaluates the wound tissue interface's structural and mechanical integrity posterior to suturing in dry conditions. Figure 4A shows the load−displacement curves for varied suture types and densities and the corresponding elastic modulus, including intact AAW, SCS-high, SCS-low, SIS-high, and SISlow.…”

Bridging the Gap in Ashby’s Map for Soft Material Properties for Tissue Engineering

“…The progressive evolution of tissue engineering started in the 20th century by constructing tissues or organs. − Futuristic-engineered tissues are anticipated to replace injured or diseased portions and provide a dynamic environment for new tissue growth. , One of the prerequisites for artificial tissues is a soft biomaterial as a scaffold/substrate, biocompatible and/or biodegradable with optimal mechanical properties and functional perdurability. However, despite the state-of-the-art developments, identifying and selecting soft biomaterial with optimal properties have been a long-standing challenge in tissue engineering.…”