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Objectives Islet transplantation is an accepted transplantation method in type I Diabetes Mellitus, yet islet survival is hampered due to an insufficient transplantation site and severe immunological and inflammatory responses. The development of a bio-artificial pancreas (BAP) may contribute to transplanted islet functionality and survival. The objective of this study is to identify the most important transplantation characteristics and to asses patients’ and endocrinologists´ preferences for three potential BAP scenarios in order to guide further development. Methods The current standard of care and characteristics that determine clinical decisions for a particular transplantation method were analysed based on a literature search, semi-structured interviews and focus groups. A decision tree was constructed covering the main attributes effectiveness, patient safety, impact of the treatment for the patient and the required amount of donor material. The analytic hierarchy process was used to obtain the relative weights for each defined attribute in type I DM patients (n=21) and endocrinologists (n=12). Based on these weights, overall preferences for three potential BAP scenarios were calculated and compared to conventional pancreas and islets transplantation. Results The three most important treatment attributes are the effectiveness of the transplant for glucose control, patient safety and the surgical procedure. However, there were considerable differences between patients and endocrinologists in the importance of effectiveness of the transplant (weights were 0.471 and 0.257 respectively) and patient safety (0.331 and 0.423). While considering both endocrinologists’ and patients’ preferences, all three BAP scenarios assessed gained a higher overall preference in comparison to conventional islet transplantation. Conclusions This study indicates the prospects of BAP development. Nevertheless, the study also highlights the discrepancies between endocrinologists’ and type 1 diabetes patients’ preferences. In the future, BAP developers can benefit from this multidisciplinary approach by critically reviewing their BAP design, in view of patient safety and clinical performance

Monitoring extracellular matrix (ECM) components is one of the key methods used to determine tissue quality in three-dimensional scaffolds for regenerative medicine and clinical purposes. Raman spectroscopy can be used for non-invasive sensing of cellular and ECM biochemistry. We have investigated the use of conventional (confocal and semiconfocal) Raman microspectroscopy and fibre-optic Raman spectroscopy for in vitro monitoring of ECM formation in three-dimensional poly(ethylene oxide terephthalate)–poly(butylene terephthalate) (PEOT/PBT) scaffolds. Chondrocyte-seeded PEOT/PBT scaffolds were analysed for ECM formation by Raman microspectroscopy, biochemical analysis, histology and scanning electron microscopy. ECM deposition in these scaffolds was successfully detected by biochemical and histological analysis and by label-free non-destructive Raman microspectroscopy. In the spectra collected by the conventional Raman set-ups, the Raman bands at 937 and at 1062 cm−1 which, respectively, correspond to collagen and sulfated glycosaminoglycans could be used as Raman markers for ECM formation in scaffolds. Collagen synthesis was found to be different in single chondrocyte-seeded scaffolds when compared with microaggregate-seeded samples. Normalized band-area ratios for collagen content of single cell-seeded samples gradually decreased during a 21-day culture period, whereas collagen content of the microaggregate-seeded samples significantly increased during this period. Moreover, a fibre-optic Raman set-up allowed for the collection of Raman spectra from multiple pores inside scaffolds in parallel. These fibre-optic measurements could give a representative average of the ECM Raman signal present in tissue-engineered constructs. Results in this study provide proof-of-principle that Raman microspectroscopy is a promising non-invasive tool to monitor ECM production and remodelling in three-dimensional porous cartilage tissue-engineered constructs.

This chapter elaborates the degradable polymers for tissue engineering and their required scaffold material in tissue engineering. It recognizes the examples of degradable polymers broadly used in tissue engineering. Tissue engineering is the persuasion of the body to heal itself through the delivery to appropriate sites of molecular signals, cells, and supporting structures. The technology of tissue engineering is being applied to (re)generate many human tissues and organs. The chapter focuses on basic aspects of polymers used in the preparation of polymeric scaffolds and matrices. An important requirement for a tissue engineering scaffold is that it degrades and resorbs at a rate that matches the formation of new tissue. Degradable polymers are suitable as scaffold material for tissue engineering as interference with the development and growth of new tissue and unwanted long-term reactions are prevented.

Micro- and nanospheres composed of biodegradable polymers show promise as versatile devices for the controlled delivery of biopharmaceuticals. Whereas important properties such as drug release profiles, biocompatibility, and (bio)degradability have been determined for many types of biodegradable particles, information about particle degradation inside phagocytic cells is usually lacking. Here, we report the use of confocal Raman microscopy to obtain chemical information about cross-linked dextran hydrogel microspheres and amphiphilic poly(ethylene glycol)-terephthalate/poly(butylene terephthalate) (PEGT/PBT) microspheres inside RAW 264.7 macrophage phagosomes. Using quantitative Raman microspectroscopy, we show that the dextran concentration inside phagocytosed dextran microspheres decreases with cell incubation time. In contrast to dextran microspheres, we did not observe PEGT/PBT microsphere degradation after 1 week of internalization by macrophages, confirming previous studies showing that dextran microsphere degradation proceeds faster than PEGT/PBT degradation. Raman microscopy further showed the conversion of macrophages to lipid-laden foam cells upon prolonged incubation with both types of microspheres, suggesting that a cellular inflammatory response is induced by these biomaterials in cell culture. Our results exemplify the power of Raman microscopy to characterize microsphere degradation in cells and offer exciting prospects for this technique as a noninvasive, label-free optical tool in biomaterials histology and tissue engineering.

This dissertation describes the use of confocal Raman microscopy and spectroscopy in the field of tissue engineering. Moreover, it describes the combination of two already existing technologies, namely scanning electron microscopy and confocal Raman spectroscopy in one apparatus for the enhancement of the chemical analytical capabilities of the electron microscope.

In many multi-disciplinary fields of science, such as tissue engineering, where material and biological sciences are combined, there is a need for a tool that combines ultrastructural and chemical data analysis in a non-destructive manner at high resolution. We show that a combination of confocal Raman spectroscopy (CRS) and scanning electron microscopy (SEM) can be used for such analysis. Studies of atomic composition can be done by X-ray microanalysis in SEM, but this is only possible for atomic numbers greater than five and does not reveal molecular identity. Raman spectroscopy, however, can provide information on molecular composition and identity by detection of wavelength shifts caused by molecular vibrations. In this study, CRS–SEM revealed that early in vitro-formed bone extracellular matrix (ECM) produced by rat osteoprogenitor cells resembles mature bone chemically. We gained insight into the structure and chemical composition of the ECM, which was composed of mainly mineralized collagen type I fibres and areas of dense carbonated calcium phosphate related to the collagen fibre density, as revealed by Raman imaging of SEM samples. We found that CRS–SEM allows the study of specimens in a non-destructive manner and provides high-resolution structural and chemical information about inorganic and organic constituents by parallel measurements on the same sample.