Nanoporous poly(methyl methacrylate)-quantum dots nanocomposite fibers toward biomedical applications

In this work, poly(methyl methacrylate) (PMMA)-CdSe/ZnS quantum dots (QDs) nanocomposite fibers were fabricated via a simple electrospinning method. The parameters including concentration of PMMA, feed rate, applied voltage and working distance between the needle tip and the fiber collecting electrode were investigated and optimized to acquire large quantity, uniform and defect-free PMMA and its QD nanocomposite fibers. The surface morphology of the fibers was characterized by scanning electron microscopy (SEM), while the fluorescence emission characteristics of the polymer nanocomposite (PNC) fibers were analyzed with fluorescence microscopy. The thermal properties of the PMMA-QDs PNC fibers were explored by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). In comparison to the pristine PMMA fibers, the PNC fibers with only 0.1 wt% QD loading showed an improved thermal stability by 15 °C for the midpoint and onset degradation temperature. Surface chemical structure and functionalities were probed by a combination of attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). New vibration bands were observed in the PNC fibers in the ATR-FTIR spectra, while the binding energy for both high resolution C 1s and O 1s spectra in the PNC fibers showed an apparent shift toward lower field. Rheological studies revealed a pseudoplastic behavior of both pristine PMMA and PMMA-QDs solutions. Moreover, the formed nanoporous PMMA-QDs fiber media exhibited an excellent biocompatibility as evidenced by the model Chinese hamster ovary (CHO) cell culturing test. The CHO cells demonstrated good adhesion, growth and viability in the reported testing.

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