Vibrational spectroscopy of polymeric biomaterials

Abstract

This review highlights the potential of vibrational spectroscopy for investigating the molecular structure of some polymeric materials used in biomedical applications in relation to their biocompatibility. Many types of polymers are used for biomedical purposes; depending on the application, bioresorbable or non-bioresorbable (semi-crystalline or amorphous) polymers are used. Among bioresorbable polymers, we focused on homopolymers and copolymers based on poly(lactic acid), poly(glycolic acid) and poly(ecaprolactone). Being a nondestructive technique, Raman spectroscopy proved particularly suitable for evaluating the molecular structure and crystallinity of bioresorbable polymers and their degradation products. For various biomedical applications, non-degradable semi-crystalline polymers have been widely employed; in this class of polymers, we concentrated on ultra-high molecular weight polyethylene (UHMWPE) used in orthopaedic implants (total hip and knee joints). Vibrational spectroscopy appeared particularly suitable in studying the oxidation and crystallinity of UHMWPE.

Diamond as pressure sensor in high‐pressure Raman spectroscopy using sapphire and other gem anvil cells

“…This conclusion has special significance for Raman studies focused on polymers and biomaterials. 28 We first confirmed that sapphire is a suitable anvil to perform Raman studies at moderately high pressures, and second we demonstrated that micrometer-sized diamonds are an excellent pressure gauge with gem anvils. From our point of view, both procedures convey important advantages, as we have shown in the preceding sections.…”

Processing, annealing and sterilisation of poly-l-lactide

“…Furthermore, the bands observed at 875 and 1452 cm À1 corresponding to the nC-COO and dCH 3 modes, respectively [28], have been used for a relative quantitative evaluation of polymeric chain length. The intensity ratio of these two peaks (I 875 /I 1452 ) has been reported by Taddei et al [29] to monitor the in vitro and in vivo degradation of the polymeric chain of PLLA devices. It was observed during their studies that the ratio decreased linearly with increasing implant time.…”

Determination of Crystallinity and Crystal Structure of Hylamer™ Polyethylene after in vivo Wear

“…It is a nondestructive method that does not need any sample preparation, which has been used for the analysis of polyethylene samples [10], since it reflects polyethylene crystals morphology [16].…”

“…Through excitation, ionization, and breakage of bonds, the kinetic energy of these electrons is transferred to the medium, and ultimately the electrons recombine with the ions in the medium, forming free radicals. As a result of these factors, maximum oxidation is found at a certain distance (typically 1-2 mm) below the surface of the UHMPWE and this subsurface band is correlated with cracking and delamination in retrieved acetabular liners [10].…”