Effect of neoadjuvant chemotherapy combined with arterial chemoembolization on short-term clinical outcome of locally advanced gastric cancer.

BACKGROUND: The purpose of this study was to explore the short-term efficacy and safety of neoadjuvant chemotherapy combined with arterial chemoembolization for locally advanced gastric cancer (LAGC). METHODS: We retrospectively analyzed the clinical data of 203 patients with LAGC who received neoadjuvant therapy from June 2019 to December 2021. The patients were divided into a neoadjuvant chemotherapy combined with arterial chemoembolization group (combined group, n = 102) and a neoadjuvant chemotherapy group (conventional group, n = 101). The adverse events of chemotherapy, postoperative complications and pathological complete response (pCR) rate were compared between the two groups. Univariate and multivariate analyses were performed to evaluate the potential factors affecting pCR. RESULTS: A total of 78.8% of the patients were in clinical stage III before neoadjuvant therapy. A total of 52.2% of the patients underwent surgery after receiving two cycles of neoadjuvant therapy. There were 21.2% patients with ≥ grade 3 (CTCAE 4.0) adverse events of chemotherapy and 11.3% patients with Clavien-Dindo classification ≥ grade 3 postoperative complications. Compared with the conventional group, the combination group did not experience an increase in the adverse events of chemotherapy or postoperative complications. The pCR rate in the combined group was significantly higher than that in the conventional group (16.7% vs. 4.95%, P = 0.012). The multivariate analysis showed that arterial chemoembolization, pre-treatment neutrophil-to-lymphocyte ratio (NLR) and pre-treatment platelet-to-lymphocyte ratio (PLR) were independent factors affecting pCR. CONCLUSION: Neoadjuvant chemotherapy combined with arterial chemoembolization contributed to improving the pCR rate of LAGC patients. Arterial chemoembolization, pre-treatment NLR and pre-treatment PLR were also predictors of pCR.

Neutral Antiaromatic Bis(1,2-dithiolene)-Chelated Nickel Complexes Bearing Multiradical Characters.

Metal-organic complexes with radical characteristics are unique species attracting immense attention in recent years due to their peculiar properties and promising applicability in a wide variety of innovative research fields. However, the reported complexes typically do not exceed diradicality. This study systematically investigates a series of square planar neutral Ni-bis(1,2-dithiolene) and Ni-bis(1,2-dioxolene) complexes with linear, branched, and macrocyclic configurations via ab initio calculations. The linear Ni-complexes display strong singlet diradical characters, while their branched counterparts can also exhibit moderate singlet multiradical characters. Importantly, the macrocyclic Ni-complexes can possess extremely strong singlet multiradical characters up to dodeca-radicality along with their global antiaromaticity and hence strong induced ring current in the presence of an external magnetic field, ascribed to the localization of unpaired α and ß electrons residing in the highest few molecular orbitals at different molecular sites, minimizing their coupling and annihilation. Our work represents the first indication in the rational design of novel multiradical neutral antiaromatic macrocyclic complexes for potential applications in molecular machines and electronic devices.

Snapshot multifocal light field microscopy.

Light field microscopy (LFM) is an emerging technology for high-speed wide-field 3D imaging by capturing 4D light field of 3D volumes. However, its 3D imaging capability comes at a cost of lateral resolution. In addition, the lateral resolution is not uniform across depth in the light field dconvolution reconstructions. To address these problems, here, we propose a snapshot multifocal light field microscopy (MFLFM) imaging method. The underlying concept of the MFLFM is to collect multiple focal shifted light fields simultaneously. We show that by focal stacking those focal shifted light fields, the depth-of-field (DOF) of the LFM can be further improved but without sacrificing the lateral resolution. Also, if all differently focused light fields are utilized together in the deconvolution, the MFLFM could achieve a high and uniform lateral resolution within a larger DOF. We present a house-built MFLFM system by placing a diffractive optical element at the Fourier plane of a conventional LFM. The optical performance of the MFLFM are analyzed and given. Both simulations and proof-of-principle experimental results are provided to demonstrate the effectiveness and benefits of the MFLFM. We believe that the proposed snapshot MFLFM has potential to enable high-speed and high resolution 3D imaging applications.

The Significance of Metal Coordination in Imidazole-Functionalized Metal-Organic Frameworks for Carbon Dioxide Utilization.

The grafting of imidazole species onto coordinatively unsaturated sites within metal-organic framework MIL-101(Cr) enables enhanced CO2 capture in close proximity to catalytic sites. The subsequent combination of CO2 and epoxide binding sites, as shown through theoretical findings, significantly improves the rate of cyclic carbonate formation, producing a highly active CO2 utilization catalyst. An array of spectroscopic investigations, in combination with theoretical calculations reveal the nature of the active sites and associated catalytic mechanism which validates the careful design of the hybrid MIL-101(Cr).

Suite of Organoplatinum(II) Triangular Metallaprism: Aggregation-Induced Emission and Coordination Sequence Induced Emission Tuning.

A series of triangular metallaprisms with a kinetically inert Pt-N bond have been synthesized from the stepwise assembly of a Pt-corner, linear linker 4,4'-bipy (4,4'-bipy = 4,4'-bipyridine) and triangular ligand [tpb or tpt, tpb = tris(4-pyridyl)benzene, tpt = tris(4-pyridyl)triazine]. The use of an unsymmetrical [Pt(HL)]-corner (H2L = 2,6-diphenylpyridine) leads to novel isostructural products. Phenyl rotation at the metal-corners endows these complexes with good aggregation-induced emission (AIE) function, with varied activities across the isostructural complexes. The coordination sequence of electron-deficient ligand tpt also imparts significant influence on the complex emission. These organoplatinum triangular metallaprisms thus provide a good model to study the influence of building blocks and coordination sequence on the luminescence of supramolecules.

Design and simulation of a snapshot multi-focal interferometric microscope.

Realizing both high temporal and spatial resolution across a large volume is a key challenge for 3D fluorescent imaging. Towards achieving this objective, we introduce an interferometric multifocus microscopy (iMFM) system, a combination of multifocus microscopy (MFM) with two opposing objective lenses. We show that the proposed iMFM is capable of simultaneously producing multiple focal plane interferometry that provides axial super-resolution and hence isotropic 3D resolution with a single exposure. We design and simulate the iMFM microscope by employing two special diffractive optical elements. The point spread function of this new iMFM microscope is simulated and the image formation model is given. For reconstruction, we use the Richardson-Lucy deconvolution algorithm with total variation regularization for 3D extended object recovery, and a maximum likelihood estimator (MLE) for single molecule tracking. A method for determining an initial axial position of the molecule is also proposed to improve the convergence of the MLE. We demonstrate both theoretically and numerically that isotropic 3D nanoscopic localization accuracy is achievable with an axial imaging range of 2um when tracking a fluorescent molecule in three dimensions and that the diffraction limited axial resolution can be improved by 3-4 times in the single shot wide-field 3D extended object recovery. We believe that iMFM will be a useful tool in 3D dynamic event imaging that requires both high temporal and spatial resolution.

CS-ToF: High-resolution compressive time-of-flight imaging.

Three-dimensional imaging using Time-of-flight (ToF) sensors is rapidly gaining widespread adoption in many applications due to their cost effectiveness, simplicity, and compact size. However, the current generation of ToF cameras suffers from low spatial resolution due to physical fabrication limitations. In this paper, we propose CS-ToF, an imaging architecture to achieve high spatial resolution ToF imaging via optical multiplexing and compressive sensing. Our approach is based on the observation that, while depth is non-linearly related to ToF pixel measurements, a phasor representation of captured images results in a linear image formation model. We utilize this property to develop a CS-based technique that is used to recover high resolution 3D images. Based on the proposed architecture, we developed a prototype 1-megapixel compressive ToF camera that achieves as much as 4× improvement in spatial resolution and 3× improvement for natural scenes. We believe that our proposed CS-ToF architecture provides a simple and low-cost solution to improve the spatial resolution of ToF and related sensors.

Compressive holographic video.

Compressed sensing has been discussed separately in spatial and temporal domains. Compressive holography has been introduced as a method that allows 3D tomographic reconstruction at different depths from a single 2D image. Coded exposure is a temporal compressed sensing method for high speed video acquisition. In this work, we combine compressive holography and coded exposure techniques and extend the discussion to 4D reconstruction in space and time from one coded captured image. In our prototype, digital in-line holography was used for imaging macroscopic, fast moving objects. The pixel-wise temporal modulation was implemented by a digital micromirror device. In this paper we demonstrate 10× temporal super resolution with multiple depths recovery from a single image. Two examples are presented for the purpose of recording subtle vibrations and tracking small particles within 5 ms.

How Does Substitutional Doping Affect Visible Light Absorption in a Series of Homodisperse Ti11 Polyoxotitanate Nanoparticles--A Comment on the Band Gap Determination of the Fe(II) Cages (Chem. Eur. J. 2015, 21, 11538).

There is no experimental support for the conclusion by Coppens and Chen in a recent paper that the (HOMO-LUMO) band gaps in a series of Fe(II) polyoxotitanate cages are in the range 1.43-1.59 eV.

High dynamic range coherent imaging using compressed sensing.

In both lensless Fourier transform holography (FTH) and coherent diffraction imaging (CDI), a beamstop is used to block strong intensities which exceed the limited dynamic range of the sensor, causing a loss in low-frequency information, making high quality reconstructions difficult or even impossible. In this paper, we show that an image can be recovered from high-frequencies alone, thereby overcoming the beamstop problem in both FTH and CDI. The only requirement is that the object is sparse in a known basis, a common property of most natural and manmade signals. The reconstruction method relies on compressed sensing (CS) techniques, which ensure signal recovery from incomplete measurements. Specifically, in FTH, we perform compressed sensing (CS) reconstruction of captured holograms and show that this method is applicable not only to standard FTH, but also multiple or extended reference FTH. For CDI, we propose a new phase retrieval procedure, which combines Fienup's hybrid input-output (HIO) method and CS. Both numerical simulations and proof-of-principle experiments are shown to demonstrate the effectiveness and robustness of the proposed CS-based reconstructions in dealing with missing data in both FTH and CDI.

Amorphous ruthenium nanoparticles for enhanced electrochemical water splitting.

This paper demonstrates an optimized fabrication of amorphous Ru nanoparticles through annealing at various temperatures ranging from 150 to 700 °C, which are used as water oxidation catalyst for effective electrochemical water splitting under a low overpotential of less than 300 mV. The amorphous Ru nanoparticles with short-range ordered structure exhibit an optimal and stable electrocatalytic activity after annealing at 250 °C. Interestingly, a small quantity of such Ru nanoparticles in a thin film on fluorine-doped tin oxide glass is also effectively driven by a conventional crystalline silicon solar cell that has excellent capability for harvesting visible light. Remarkably, it achieves an overall solar-to-hydrogen efficiency of 11.3% in acidic electrolyte.

The Variation in Chemical Composition and Source Apportionment of PM2.5 before, during, and after COVID-19 Restrictions in Zhengzhou, China.

Despite significant improvements in air quality during and after COVID-19 restrictions, haze continued to occur in Zhengzhou afterwards. This paper compares ionic compositions and sources of PM2.5 before (2019), during (2020), and after (2021) the restrictions to explore the reasons for the haze. The average concentration of PM2.5 decreased by 28.5% in 2020 and 27.9% in 2021, respectively, from 102.49 µg m-3 in 2019. The concentration of secondary inorganic aerosols (SIAs) was 51.87 µg m-3 in 2019, which decreased by 3.1% in 2020 and 12.8% in 2021. In contrast, the contributions of SIAs to PM2.5 increased from 50.61% (2019) to 68.6% (2020) and 61.2% (2021). SIAs contributed significantly to PM2.5 levels in 2020-2021. Despite a 22~62% decline in NOx levels in 2020-2021, the increased O3 caused a similar NO3- concentration (20.69~23.00 µg m-3) in 2020-2021 to that (22.93 µg m-3) in 2019, hindering PM2.5 reduction in Zhengzhou. Six PM2.5 sources, including secondary inorganic aerosols, industrial emissions, coal combustion, biomass burning, soil dust, and traffic emissions, were identified by the positive matrix factorization model in 2019-2021. Compared to 2019, the reduction in PM2.5 from the secondary aerosol source in 2020 and 2021 was small, and the contribution of secondary aerosol to PM2.5 increased by 13.32% in 2020 and 12.94% in 2021. In comparison, the primary emissions, including biomass burning, traffic, and dust, were reduced by 29.71% in 2020 and 27.7% in 2021. The results indicated that the secondary production did not significantly contribute to the PM2.5 decrease during and after the COVID-19 restrictions. Therefore, it is essential to understand the formation of secondary aerosols under high O3 and low precursor gases to mitigate air pollution in the future.

CircGPRC5A enhances colorectal cancer progress by stabilizing PPP1CA and inducing YAP dephosphorylation.

BACKGROUND: With the advancements in bioinformatic technology, an increasing number of circular RNAs (circRNAs) have been discovered and their crucial roles in the development and progression of various malignancies have been confirmed through multiple pathways. However, the specific mechanisms involving protein-binding circRNAs in colorectal cancer (CRC) remain largely unexplored. METHODS: Differential circRNA expression was assessed using a human circRNA microarray in five CRC tissue and paired normal samples. CircGPRC5A expression was then confirmed in the CRC tissues and paired normal samples using qRT-PCR. The biological function of circGPRC5A in CRC were studied in vitro and in vivo. Western blotting, fluorescence in situ hybridization, immunofluorescence, RNA pulldown, mass spectrometry, immunoprecipitation, quantitative phosphoproteomics, and RNA-binding protein immunoprecipitation assays were used to study circGPRC5A. RESULTS: Our analysis revealed that circGPRC5A expression was higher in CRC tissues compared to normal tissues and was associated with tumor size, tumor stage and lymph node status. CircGPRC5A promoted CRC cell proliferation, migration, and metastasis in vitro and in vivo. CircGPRC5A could stabilize PPP1CA protein by inhibiting the binding between UBA1 and PPP1CA, and increasing YAP dephosphorylation. CONCLUSIONS: Our study revealed that circGPRC5A plays an essential function in CRC progression by stabilizing PPP1CA protein and enhancing YAP dephosphorylation. CircGPRC5A could act as a novel and potential target for CRC.

Associations between cognition, anxiety, depression, and residual dizziness in elderly people with BPPV.

Objective: To investigate the associations between cognition, anxiety, depression, and residual dizziness after successful repositioning maneuvers in the elderly with benign paroxysmal positional vertigo (BPPV). Methods: We enrolled 40 elderly patients with BPPV in our outpatient department. We used the Dizziness Handicap Inventory (DHI), Visual Analog Scale (VAS), Patient Health Questionnaire-9 (PHQ-9), and Generalized Anxiety Disorder Questionnaire-7 (GAD-7) to assess the degree of dizziness, anxiety, and depression of participants before repositioning therapy, respectively. At the 1-week follow-up after BPPV treatment, each participant will be reassessed and divided into a group with residual dizziness (RD) and a group without residual dizziness (NRD) based on the follow-up DHI score. The Mini-Mental State Examination (MMSE) evaluated the cognitive function of the participants. Results: The age, gender, duration of BPPV, and involved semicircular canals in the two groups did not show a significant difference. The RD group scored significantly higher on the DHI (p = 0.006), GAD-7 (p < 0.001), and PHQ-9 (p = 0.002) before the repositioning treatment than the NRD group. The two groups had no significant difference in MMSE score (p = 0.381). Anxiety and depression scores before repositioning treatment significantly and positively correlated with follow-up DHI scores (r = 0.678 and 0.522, respectively), but the MMSE score did not significantly relate to it. The univariate linear regression showed that the DHI (p < 0.001), GAD-7 (p < 0.001), and PHQ-9 (p = 0.002) scores before treatment could predict residual dizziness. The multivariate linear regression showed that GAD-7 before treatment was the only significant predictor of residual dizziness (p < 0.001). Conclusion: The level of dizziness, anxiety, and depression before treatment can predict residual dizziness after successful repositioning maneuvers in the elderly with BPPV. Anxiety may be the strongest predictor of residual dizziness after successful repositioning treatment in elderly BPPV patients.

Antifouling polymers for nanomedicine and surfaces: recent advances.

Antifouling polymers are materials that can resist nonspecific interactions with cells, proteins, and other biomolecules. Typically, they are hydrophilic polymers with polar or charged moieties that are capable of strong nonbonding interactions with water molecules. This propensity to bind water generates a surface hydration layer that reduces nonspecific interactions with other molecules and is paramount to the antifouling behavior. This property is especially useful for nanoscale applications such as nanomedicine and surface modifications at the molecular level. In nanomedicine, antifouling polymers such as poly(ethylene glycol) and its alternatives play a key role in shielding drug molecules and therapeutic proteins/genes from the immune system within nanoassemblies, thereby enabling effective delivery to target tissues. For coatings, antifouling polymers help to prevent adhesion of cells and molecules to surfaces and are thus valued in marine and biomedical device applications. In this Review, we survey recent advances in antifouling polymers in the context of nanomedicine and coatings, while shining the spotlight on the major polymer classes such as PEG, polyzwitterions, poly(oxazoline)s, and other nonionic hydrophilic polymers.

The functional status of vestibular otolith and conductive pathway in patients with unilateral idiopathic sudden sensorineural hearing loss.

Background: The cause of idiopathic sudden sensorineural hearing loss (ISSNHL) remains unknown. It has been found that the functional status of the vestibular otolith is relevant to its prognosis; however, the evaluation of the vestibular otolith (intra-labyrinth) and superior and inferior vestibular nerve pathways (retro-labyrinth) in ISSNHL patients is not well-documented. Objective: This study aimed to investigate the functional status of the vestibular otolith and conductive pathway in patients with unilateral ISSNHL and analyze the correlations between vestibular evoked myogenic potentials (VEMPs) and hearing improvement after treatment. Methods: A total of 50 patients with unilateral ISSNHL underwent a battery of audio-vestibular evaluations, including pure tone audiometry, middle ear function, air-conducted sound-cervical VEMP (ACS-cVEMP), ACS-ocular VEMP (ACS-oVEMP), galvanic vestibular stimulation-cervical VEMP (GVS-cVEMP), and GVS-ocular VEMP (GVS-oVEMP). The results of auditory and VEMPs were retrospectively analyzed. Results: The abnormal rates of ACS-cVEMP, ACS-oVEMP, GVS-cVEMP, and GVS-oVEMP in affected ears were 30, 52, 8, and 16%, respectively. In affected ears, the abnormal rate of ACS-oVEMP was significantly higher than that of ACS-cVEMP (p = 0.025), while it was similar between GVS-cVEMP and GVS-oVEMP (p = 0.218). Compared with GVS-cVEMP, affected ears presented with a significantly higher abnormal rate of ACS-cVEMP (p = 0.005), and the abnormal rate of ACS-oVEMP was significantly higher than that of GVS-oVEMP (p < 0.001). No significant difference existed in latency and amplitude between affected and unaffected ears in ACS-VEMPs or GVS-VEMPs (p > 0.05). The abnormal rate of VEMPs in the poor recovery group was significantly higher than that of the good recovery group (p = 0.040). The abnormality percentages of ACS-oVEMP and GVS-oVEMP in the poor recovery group were significantly higher than that of the good recovery group (p = 0.004 and 0.039, respectively). The good hearing recovery rates were 76.47% in the normal VEMPs group, 58.33% in the intra-labyrinth lesion group, and 22.22% in the retro-labyrinth lesion group. Hearing recovery worsened as a greater number of abnormal VEMPs was presented. Conclusion: Besides Corti's organ, the impairment of otolithic organs was prominent in patients with ISSNHL. The normal VEMPs group had the highest rate of good recovery, followed by the intra-labyrinth lesion group and the retro-labyrinth lesion group presented with the lowest recovery rate. Abnormalities in ACS-oVEMP and/or GVS-oVEMP were indicators of a poor prognosis.

Dopamine and cyclic adenosine monophosphate-regulated phosphoprotein with an apparent Mr of 32000 promotes colorectal cancer growth.

BACKGROUND: Dopamine and cyclic adenosine monophosphate (cAMP)-regulated phosphoprotein with an apparent Mr of 32000 (DARPP-32) is a protein that is involved in regulating dopamine and cAMP signaling pathways in the brain. However, recent studies have shown that DARPP-32 is also expressed in other tissues, including colorectal cancer (CRC), where its function is not well understood. AIM: To explore the effect of DARPP-32 on CRC progression. METHODS: The expression levels of DARPP-32 were assessed in CRC tissues using both quantitative polymerase chain reaction and immunohistochemistry assays. The proliferative capacity of CRC cell lines was evaluated with Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays, while apoptosis was measured by flow cytometry. The migratory and invasive potential of CRC cell lines were determined using wound healing and transwell chamber assays. In vivo studies involved monitoring the growth rate of xenograft tumors. Finally, the underlying molecular mechanism of DARPP-32 was investigated through RNA-sequencing and western blot analyses. RESULTS: DARPP-32 was frequently upregulated in CRC and associated with abnormal clinicopathological features in CRC. Overexpression of DARPP-32 was shown to promote cancer cell proliferation, migration, and invasion and reduce apoptosis. DARPP-32 knockdown resulted in the opposite functional effects. Mechanistically, DARPP-32 may regulate the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway in order to carry out its biological function. CONCLUSION: DARPP-32 promotes CRC progression via the PI3K/AKT signaling pathway.

P300 Event-Related Potential Predicts Cognitive Dysfunction in Patients with Vestibular Disorders.

OBJECTIVE: Our aim was to determine the correlation between cognitive impairment and P300 event-related potential (ERP) in older adults with vertigo and imbalance, which further provides a reference for clinical diagnosis and patients' rehabilitation. METHODS: A total of 79 older adult patients with vertigo and imbalance in our outpatient department from January 2022 to December 2022 were selected and divided into the mild group (n = 20), moderate group (n = 39), and severe group (n = 20) according to the Dizziness Handicap Inventory (DHI). The auditory P300 component of event-related potentials (ERPs), Generalized Anxiety Disorder Questionnaire-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), and Mini-Mental State Examination (MMSE) were used to evaluate depression, anxiety, and cognitive function in these patients, respectively. RESULTS: The P300 latencies of the different severity groups were 292 ± 10 ms, 301 ± 8 ms, and 328 ± 5 ms, respectively, and the differences were statistically significant (p = 0.010). The P300 amplitudes of the different severity groups were 14.4 ± 2.6 µV, 3.9 ± 0.8 µV, and 5.1 ± 1.4 µV, respectively, and the differences were also statistically significant (p = 0.004). There was no statistically significant difference in the DHI evaluation or VAS visual simulation scoring between the two groups (p = 0.625, and 0.878, respectively). Compared with the short-course group, the long-course group showed prolonged P300 latency and decreased amplitude, higher scores in PHQ-9 and GAD-7, and lower scores in MMSE, and all the differences were statistically significant (p = 0.013, 0.021, 0.006, 0.004, and 0.018, respectively). CONCLUSION: Older patients with more severe symptoms of vertigo and imbalance are at higher risk of developing abnormal cognitive function. The P300 can be used as an objective neurophysiological test for the assessment of cognitive function relevant to elderly patients with vertigo and imbalance.

Guanidinium-Perfunctionalized Polyhedral Oligomeric Silsesquioxanes as Highly Potent Antimicrobials against Planktonic Microbes, Biofilms, and Coronavirus.

Supramolecules have been drawing increasing attention recently in addressing healthcare challenges caused by infectious pathogens. We herein report a novel class of guanidinium-perfunctionalized polyhedral oligomeric silsesquioxane (Gua-POSS) supramolecules with highly potent antimicrobial activities. The modular structure of Gua-POSS Tm-Cn consists of an inorganic T10 or T8 core (m = 10 or 8), flexible linear linkers of varying lengths (n = 1 or 3), and peripherally aligned cationic guanidinium groups as the membrane-binding units. Such Gua-POSS supramolecules with spherically arrayed guanidinium cations display high antimicrobial potency against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, as well as fungus (Candida albicans), with the best showing excellently low minimal inhibitory concentrations (MICs) of 1.7-6.8 µM in media, yet with negligible hemolytic activity and low in vitro cytotoxicity to mammalian cells. More significantly, they can inhibit biofilm formation at around their MICs and near-completely break down preestablished difficult-to-break biofilms at 250 µg mL-1 (∼50 µM). Their strong antiviral efficacy was also experimentally demonstrated against the enveloped murine hepatitis coronavirus as a surrogate of the SARS-CoV species. Overall, this study provides a new design approach to novel classes of sphere-shaped organic-inorganic hybrid supramolecular materials, especially for potent antimicrobial, anti-biofilm, and antiviral applications.

Visible Light Degradable Acridine-Containing Polyurethanes in an Aqueous Environment.

Light degradable polymers hold significant promise in a wide range of applications including the fabrication of optically recyclable materials, responsive coatings and adhesives, and controlled drug delivery. Here, we report the synthesis of polyurethanes that can be degraded under irradiation of visible light (≤450 nm) from commercial LED (3-15 W) light sources. The photolysis occurs in an aqueous environment via photocleavage of an acridine moiety incorporated within the backbone of the polymer chains. Analysis of the quantum yield as a function of wavelength reveals highly efficient photoreactivity at up to 440 nm activation, which is red-shifted compared to the UV-vis absorbance of the chromophore. The potential of our chemical system in biomaterials is demonstrated by the fabrication of an in situ forming hydrogel that can be degraded by visible light.