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Projection-microstereolithography is an additive manufacturing technique based on the spatially controlled solidification of a liquid photopolymer on exposure to digitally manipulated light patterns. This study presents a methodology to evaluate the effect of a type-I photoinitiator on the reaction kinetics in the process and the cytocompatibility of the produced components. While the reaction speed and degree of conversion were heavily dependent on the applied amount of the initiator, a clear toxic effect was observed with all tested concentrations, and a post-processing step of 7 days was required to leach out the initiator residues.

Alpha-synuclein (αS) is a natively unfolded protein with a C-terminus that is enriched with acidic residues. Three independent mutants (i.e., A30P, A53T and E46K) were identified in the genetic study of familial Parkinson's disease. Wild-type αS has been shown to possess a consistent secondary structure composition (Thomas D. Kim et al, 2000) at various temperatures. Other studies indicate that the acidic tail of αS plays an important role in preventing the protein's aggregation (Sang Myun Park et al, 2002). Here we show that both the wild-type and mutated proteins have a similar response to heat in our MD simulations. The mutant models were obtained by mutating the NMR minimized average structure of αS (PDB ID = 1XQ8). Atomistic simulations for both wild-type and mutated αS in explicit water were conducted for at least 30 ns at four different temperatures (i.e., 310 K, 330 K, 350 K and 372 K) using the CHARMM22/CMAP force field. For wild-type αS, the percentage of α-helix changed by less than 5% from that of the NMR structure regardless of simulation temperature. For each mutant αS, the percentage of α-helix differed by 10% or less regardless of simulation temperature. In all simulations, the acidic tail of αS remained predominantly random coil. Moreover, at 372 K, beta sheet was temporarily observed within a small region (approximately 3%) for the wild-type and A30P mutant.

Alpha-synuclein (αS) belongs to a natively unstructured protein family. The misfolded αS is recognized as a possible causative agent in the pathogenesis of Parkinson's disease (PD). Genetic studies have identified two dominant mutations A30P and A53T, which are associated with the early onset of PD. We show here that these two mutants observably affect the folding process of αS in a water box. Based on the NMR minimized average structure (PDB ID = 1XQ8) of the wild type (WT) αS, three mutated αS models are created: αS with mutation A30P; αS with mutation A53T; αS with mutation A30P and A53T. The WT αS model is also used for comparison. For each simulated system, which contains a monomeric protein and a water box, the temperature and pressure were set as constant: 300K and 1atm. Atomistic simulations were performed for 30 ns each, using CHARMM22/CMAP force field (MacKerell et al, 2004). Then, using the MARTINI force field v2.1 (Marrink et al, 2008), coarse-grained simulations were performed for 400ns each to simulate the conformation changes of αS over a longer time scale. The coarse-grained simulations demonstrate similar equilibrium structures for both mutated and WT αS systems. In addition, the atomistic simulations indicate that the two mutations significantly increase the rate of denaturation in the N terminus.