Novel nanocomposites based on type I collagen (Col) containing a small amount (17.4, 43.5, and 174 ppm) of gold nanoparticles (AuNPs, approximately 5 nm) were prepared in this study. The pure Col and Col-AuNP composites (Col-Au) were characterized by the UV-Vis spectroscopy (UV-Vis), surface-enhanced raman spectroscopy (SERS) and atomic force microscopy (AFM). The interaction between Col and AuNPs was confirmed by infrared (IR) spectra. The effect of AuNPs on the biocompatibility of Col, evaluated by the proliferation and reactive oxygen species (ROS) production of mesenchymal stem cells (MSCs) as well as the activation of monocytes and platelets, was investigated. Results showed that Col-Au had better biocompatibility than Col. Upon stimulation by vascular endothelial growth factor (VEGF) and stromal derived factor-1α (SDF-1α), MSCs expressed the highest levels of αvβ3 integrin/CXCR4, focal adhesion kinase (FAK), matrix metalloproteinase-2 (MMP-2), and Akt/endothelial nitric oxide synthase (eNOS) proteins when grown on the Col-Au (43.5 ppm) nanocomposite. Taken together, Col-Au nanocomposites may promote the proliferation and migration of MSCs and stimulate the endothelial cell differentiation. These results suggest that Col-Au may be used to construct tissue engineering scaffolds for vascular regeneration.

Benzo[a]pyrene (BaP), a component of cooking oil fumes (COF), promotes lung cancer cell proliferation and survival via the induction of inhibitor of apoptosis protein-2 (IAP-2) proteins. Thus knockdown of IAP-2 would be a promising way to battle against lung cancer caused by COF. Functionalized gold nanoparticle (AuNP) is an effective delivery system for bio-active materials. Here, biocompatible hyaluronic acid (HA) was fabricated into nanoparticles to increase the target specificity by binding to CD44-over-expressed cancer cells. IAP-2-specific small-interfering RNA (siRNAs) or fluorescein isothiocyanate (FITC) were then incorporated into AuNP-HA. Conjugation of IAP-2 siRNA into AuNPs-HA was verified by the UV-vis spectrometer and Fourier transform infrared spectrometer. Further studies showed that AuNP-HA/FITC were effectively taken up by A549 cells through CD44-mediated endocytosis. Incubation of BaP-challenged cells with AuNP-HA-IAP-2 siRNAs silenced the expression of IAP-2, decreased cell proliferation and triggered pronounced cell apoptosis by the decrease in Bcl-2 protein and the increase in Bax protein as well as the active form of caspases-3. The BaP-elicited cell migration and enzymatic activity of the secreted matrix metalloproteinase-2 were also substantially suppressed by treatment with AuNP-HA-IAP-2 siRNAs. These results indicated that IAP-2 siRNAs can be efficiently delivered into A549 cells by functionalized AuNP-HA to repress the IAP-2 expression and BaP-induced oncogenic events, suggesting the potential therapeutic application of IAP-2 siRNA or other siRNA-conjugated AuNP-HA composites to COF-induced lung cancer and other gene-caused diseases in the future.

The origin band in the b̃(1)B(1)-ã(1)A(1) transition of CH(2) near 1.2 μm has been recorded at Doppler-limited resolution using diode laser transient absorption spectroscopy. The assignments of rotational transitions terminating in upper state levels with K(a) = 0 and 1, were confirmed by ground state combination differences and extensive optical-optical double resonance experiments. The assigned lines are embedded in a surprisingly dense spectral region, which includes a strong hot band, b̃(0,1,0) K(a) = 0 - ã(0,1,0) K(a) = 1 sub-band lines, with combination or overtone transitions in the ã(1)A(1) state likely responsible for the majority of unassigned transitions in this region. From measured line intensities and an estimate of the concentration of CH(2) in the sample, we find the transition moment square for the 0(00) ← 1(10) transition in the b̃(1)B(1)(0,0,0)(0)-ã(1)A(1)(0,0,0)(1) sub-band is 0.005(1) D(2). Prominent b̃(1)B(1)(0,1,0)(0)-ã(1)A(1)(0,1,0)(1) hot band lines were observed in the same spectral region. Comparison of the intensities of corresponding rotational transitions in the two bands suggests the hot band has an intrinsic strength approximately 28 times larger than the origin band. Perturbations of the excited state K(a) = 0 and 1 levels are observed and discussed. The new measurements will lead to improved future theoretical modeling and calculations of the Renner-Teller effect between the ã and b̃ states in CH(2).