Clinical and Genomic Evolution of Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections over Two Time Periods at a Tertiary Care Hospital in South India: A Prospective Cohort Study.

INTRODUCTION: The objective of this study was to examine the evolution of carbapenem-resistant Klebsiella pneumoniae (CRKp) infections and their impact at a tertiary care hospital in South India. METHODS: A comparative analysis of clinical data from two prospective cohorts of patients with CRKp bacteremia (C1, 2014-2015; C2, 2021-2022) was carried out. Antimicrobial susceptibilities and whole genome sequencing (WGS) data of selected isolates were also analyzed. RESULTS: A total of 181 patients were enrolled in the study, 56 from C1 and 125 from C2. CRKp bacteremia shifted from critically ill patients with neutropenia to others (ICU stay: C1, 73%; C2, 54%; p = 0.02). The overall mortality rate was 50% and the introduction of ceftazidime-avibactam did not change mortality significantly (54% versus 48%; p = 0.49). Oxacillinases (OXA) 232 and 181 were the most common mechanisms of resistance. WGS showed the introduction of New Delhi metallo-ß-lactamase-5 (NDM-5), higher genetic diversity, accessory genome content, and plasmid burden, as well as increased convergence of hypervirulence and carbapenem resistance in C2. CONCLUSIONS: CRKp continues to pose a significant clinical threat, despite the introduction of new antibiotics. The study highlights the evolution of resistance and virulence in this pathogen and the impact on patient outcomes in South India, providing valuable information for clinicians and researchers.

Persistent bacteremia predicts poor outcomes among neutropenic patients with carbapenem-resistant gram-negative bloodstream infections receiving appropriate therapy.

PURPOSE: Identifying persistent bacteremia early in patients with neutropenia may improve outcome. This study evaluated the role of follow-up blood cultures (FUBC) positivity in predicting outcomes among patients with neutropenia and carbapenem-resistant gram-negative bloodstream infections (CRGNBSI). METHODS: This retrospective cohort study conducted between December 2017 and April 2022 included patients more than 15 years old with neutropenia and CRGNBSI, who survived for ≥ 48 h, receiving appropriate antibiotic therapy and had FUBCs. Patients with polymicrobial bacteremia within 30 days were excluded. The primary outcome was 30 day mortality. Persistent bacteremia, septic shock, recovery from neutropenia, prolonged or profound neutropenia, requirement of intensive care and dialysis, and initiation of appropriate empirical therapy were also studied. RESULTS: In our study cohort of 155 patients, the 30 day mortality rate was 47.7%. Persistent bacteremia was common in our patient cohort (43.8%). Carbapenem resistant isolates identified in the study were K.pneumoniae (80%), E.coli (12.26%), P.aeruginosa (5.16%), A.baumanii (1.94%) and E.cloacae (0.65%). The median time for sending a FUBC was 2 days (IQR, 1-3 days). Patients with persistent bacteremia had higher mortality than those without (56.76% versus 32.1%; p < 0.001). Appropriate initial empirical therapy was given to 70.9%. Recovery from neutropenia occurred in 57.4% while 25.8% had prolonged or profound neutropenia. Sixty-nine percent (107/155) had septic shock and needed intensive care; 12.2% of patients required dialysis. Non-recovery from neutropenia (aHR, 4.28; 95% CI 2.53-7.23), presence of septic shock (aHR, 4.42; 95%CI 1.47-13.28), requirement of intensive care (aHR,3.12;95%CI 1.23-7.93), and persistent bacteremia (aHR,1.74; 95%CI 1.05-2.89) significantly predicted poor outcomes in multivariable analysis. CONCLUSION: FUBC showing persistent bacteremia predicted poor outcomes among neutropenic patients with carbapenem-resistant gram-negative bloodstream infections (CRGNBSI) and should be routinely reported.

MnCo2S4 - MXene: A novel hybrid electrode material for high performance long-life asymmetric supercapattery.

The supercapattery, an ideal electrochemical energy storage device, which can deliver high energy like battery and high power like supercapacitor. Transition metal sulphides' energy storage capabilities have unfurled beyond the realm of ruthenium and manganese-based oxides by the versatile affordable sulphospinel transition metal sulphides such as MnCo2S4 (MCS). The advancement of synergistic nano-architectures of these transition metal sulphides with two-dimensional MXene material adulated the conductivity and highly reversible redox nature. The hybrid MCS-MXene was synthesised through facile cost effective hydrothermal method and the material were characterised using basic X-Ray Diffraction (XRD) to advanced tools as like electron energy loss spectroscopy (EELS). The electrochemical results depict that the supercapattery electrode of 2D synergistic MCS-MXene hybrid architectures shows highly improved specific capacitance of 600 C/g at 1 A/g current density than pristine MXene and MCS. The fabricated asymmetric supercapattery using hybrid MCS-MXene and bio-derived activated carbon (AC) shows a high specific energy and power density of 25.6 Wh/kg and 6400 W/kg, respectively with excellent cycling stability of 100% capacitance retention after 12,000 cycles.

Augmenting the electrochemical performance of NiMn2O4 by doping of transition metal ions and compositing with rGO.

The transition metal ions (TMIs) such as Co2+ and Zn2+ doped NiMn2O4 (NMO)/rGO nanocomposite synthesized by facile sol-gel method was used for the fabrication of supercapacitor. The presence of metal ions in the nanocomposite was confirmed by X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscope (HR-TEM) mapping techniques. The fabricated electrode showed high specific capacitance of 710 F/g which was 3-fold higher than NMO (254 F/g). The addition of RGO in the nanocomposite increased the cycle stability of TMIs doped NMO significantly from 51 to 91%. In addition, the symmetric supercapacitor (SSC) fabricated using TMIs doped NMO/rGO nanocomposite with 3.5 M KOH as an electrolyte delivered a maximum energy density of 43 Wh/kg and power density of 10 kW/kg. Furthermore, the SSC device retained 90% of capacitance retention over 10,000 cycles with coulombic efficiency of 99% at 5 A/g. These result suggested that the TMIs doped NMO/rGO nanocomposite electrode is a promising material for high-energy supercapacitors.

CoS2 engulfed ultra-thin S-doped g-C3N4 and its enhanced electrochemical performance in hybrid asymmetric supercapacitor.

This work demonstrates a high-performance hybrid asymmetric supercapacitor (HASC) workable in very high current density of 30 A g-1 with in-situ pyrolytic processed sulfur-doped graphitic carbon nitride/cobalt disulfide (S-gC3N4/CoS2) materials and bio-derived carbon configuration and achievement of high electrochemical stability of 89% over 100,000 cycles with the coulombic efficiency of 99.6%. In the electrochemical studies, the S-gC3N4/CoS2-II electrode showed a high specific capacity of 180 C g-1 at 1 A g-1 current density in the half-cell configuration. The HASC cell was fabricated using S-gC3N4/CoS2-II material and orange peel derived activated carbon as a positive and negative electrode with a maximum operating cell potential of 1.6 V, respectively. The fabricated HASC delivered a high energy density of 26.7 Wh kg-1 and power density of 19.8 kW kg-1 in aqueous electrolyte. The prominent properties in specific capacity and cycling stability could be attributed to the CoS2 nanoparticles engulfed into the S-gC3N4 framework which provides short transport distance of the ions, strong interfacial interaction, and improving structural stability of the S-gC3N4/CoS2-II materials.

Hydrothermal synthesis of cobalt telluride nanorods for a high performance hybrid asymmetric supercapacitor.

Cobalt telluride nanostructured materials have demonstrated various applications, particularly in energy generation and storage. A high temperature and reducing atmosphere are required for the preparation of cobalt telluride-based materials, which makes this a difficult and expensive process. The development of a facile route for producing the desirable nanostructure of cobalt telluride remains a great challenge. We demonstrated a simple hydrothermal method for preparing cobalt telluride nanorods (CoTe NRs) and telluride nanorods (Te NRs) for supercapacitor applications. The morphology of CoTe NRs and Te NRs was analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The prepared CoTe NR electrode material exhibited a high specific capacity of 170 C g-1 at a current density of 0.5 A g-1 with an exceptional cyclic stability. The asymmetric supercapacitor was assembled using CoTe NRs and orange peel-derived activated carbon (OPAA-700) as a positive and negative electrode, respectively. The fabricated device delivered a high energy density of 40.7 W h kg-1 with a power density of 800 W kg-1 at 1 A g-1 current density. When the current density was increased to 30 A g-1, the fabricated device delivered a high power density of 22.5 kW kg-1 with an energy density of 16.3 W h kg-1. The fabricated asymmetric supercapacitor displayed a good cyclic stability performance for 10 000 cycles at a high current density of 30 A g-1 and retained 85% of its initial capacity for after 10 000 cycles. The prepared materials indicate their applicability for high performance energy storage devices.

Rodenticidal hepatotoxicity: Raised plasma Von Willebrand factor levels predict in-hospital survival and preliminary report of the outcome of Von Willebrand factor reducing management protocol.

BACKGROUND: High Von Willebrand factor (VWF) levels may predispose to multi-organ failure in acute liver failure (ALF). In rodenticide-induced hepatotoxicity patients, we analyzed if plasma VWF levels predicted survival and also the outcome of VWF lowering by N-acetyl cysteine (NAC), fresh frozen plasma (FFP) infusions, and plasma exchange (PLEX). METHODS: We retrospectively analyzed prospectively collected data. Hepatotoxicity was classified as uncomplicated acute hepatitis (UAH), acute liver injury (ALI), and ALF. ALF patients, if not opting for liver transplantation, had PLEX and NAC; ALI patients received NAC ± FFP (PLEX, if worsening); UAH patients had NAC. Plasma VWF antigen was measured (normal, 50% to 150%). In-hospital survival was analyzed as discharged alive or died/discharged in a terminal condition (poor outcome). RESULTS: Twenty-four consecutive rodenticide-induced hepatotoxicity patients (UAH in 1, ALI in 20, ALF in 3) from December 2017 to January 2019 were studied. Baseline VWF levels were 153%, 423 (146-890)% median (range), and 448 (414-555)% in UAH, ALI, ALF patients; model for end-stage liver disease (MELD) scores were 11, 24 (12-38), 36 (32-37) and in-hospital survival rates were 100%, 85%, 67%, respectively. VWF levels were higher in patients with poor outcome (555 [512-890]%) than in those discharged alive (414 [146-617]%) (p-value = 0.04). The area under the receiver operating curve of the VWF level, MELD score, and sequential organ failure assessment score to predict survival was 0.92, 0.84, and 0.66, respectively. Of 4 patients meeting criteria for liver transplantation (none had transplantation), 3 (75%) survived. CONCLUSIONS: High VWF levels predict poor outcome in rodenticide-induced hepatotoxicity. VWF reduction may be useful in such patients.

Dominance of international high-risk clones in carbapenemase-producing Pseudomonas aeruginosa: Multicentric molecular epidemiology report from India.

BACKGROUND: Pseudomonas aeruginosa is one of the most common opportunistic pathogens that cause severe infections in humans. The burden of carbapenem resistance is particularly high and is on the rise. Very little information is available on the molecular mechanisms and its clonal types of carbapenem-resistant P. aeruginosa seen in Indian hospitals. This study was undertaken to monitor the ß-lactamase profile and to investigate the genetic relatedness of the carbapenemase-producing (CP) P. aeruginosa collected across different hospitals from India. MATERIALS AND METHODS: A total of 507 non-duplicate, carbapenem-resistant P. aeruginosa isolated from various clinical specimens collected during 2014-2017 across seven Indian hospitals were included. Conventional multiplex polymerase chain reaction for the genes encoding beta-lactamases such as extended-spectrum beta-lactamase (ESBL) and carbapenemase were screened. A subset of isolates (n = 133) of CP P. aeruginosa were genotyped by multilocus sequence typing (MLST) scheme. RESULTS: Of the total 507 isolates, 15%, 40% and 20% were positive for genes encoding ESBLs, carbapenemases and ESBLs + carbapenemases, respectively, whilst 25% were negative for the ß-lactamases screened. Amongst the ESBL genes, blaVEB is the most predominant, followed by blaPER and blaTEM, whilst blaVIM and blaNDM were the most predominant carbapenemases seen. However, regional differences were noted in the ß-lactamases profile across the study sites. Genotyping by MLST revealed 54 different sequence types (STs). The most common are ST357, ST235, ST233 and ST244. Six clonal complexes were found (CC357, CC235, CC244, CC1047, CC664 and CC308). About 24% of total STs are of novel types and these were found to emerge from the high-risk clones. CONCLUSION: This is the first large study from India to report the baseline data on the molecular resistance mechanisms and its association with genetic relatedness of CP P. aeruginosa circulating in Indian hospitals. blaVIM- and blaNDM-producing P. aeruginosa is the most prevalent carbapenemase seen in India. Majority of the isolates belongs to the high-risk international clones ST235, ST357 and ST664 which is a concern.

Aloe vera Derived Activated High-Surface-Area Carbon for Flexible and High-Energy Supercapacitors.

Materials which possess high specific capacitance in device configuration with low cost are essential for viable application in supercapacitors. Herein, a flexible high-energy supercapacitor device was fabricated using porous activated high-surface-area carbon derived from aloe leaf (Aloe vera) as a precursor. The A. vera derived activated carbon showed mesoporous nature with high specific surface area of ∼1890 m2/g. A high specific capacitance of 410 and 306 F/g was achieved in three-electrode and symmetric two-electrode system configurations in aqueous electrolyte, respectively. The fabricated all-solid-state device showed a high specific capacitance of 244 F/g with an energy density of 8.6 Wh/kg. In an ionic liquid electrolyte, the fabricated device showed a high specific capacitance of 126 F/g and a wide potential window up to 3 V, which results in a high energy density of 40 Wh/kg. Furthermore, it was observed that the activation temperature has significant role in the electrochemical performance, as the activated sample at 700 °C showed best activity than the samples activated at 600 and 800 °C. The electron microscopic images (FE-SEM and HR-TEM) confirmed the formation of pores by the chemical activation. A fabricated supercapacitor device in ionic liquid with 3 V could power up a red LED for 30 min upon charging for 20s. Also, it is shown that the operation voltage and capacitance of flexible all-solid-state symmetric supercapacitors fabricated using aloe-derived activated carbon could be easily tuned by series and parallel combinations. The performance of fabricated supercapacitor devices using A. vera derived activated carbon in all-solid-state and ionic liquid indicates their viable applications in flexible devices and energy storage.

Evaluation of Kumaon hill goats for resistance to natural infection with gastrointestinal nematodes.

The present study deals with the investigation of different degrees of genetic resistance/resilience of Uttarakhand hill goats to natural infection with gastrointestinal nematodes in order to introduce into breeding schemes. Animals were naturally infected with Haemonchus contortus, Teladorsagia circumcincta, Oesophagostomum spp. and Trichostrongylus spp. Faecal egg counts (FEC) were carried out every month for a period of 1 year and blood samples were collected every third month for the determination of indicator traits such as FEC, packed cell volume (PCV) and haemoglobin (Hb). The mean egg per gram (EPG), PCV and Hb were 1,579.6 ± 346, 35.12 ± 1.1 and 8.7 ± 0.2, respectively. The goats were divided into three groups (<800, 801-2,000 and >2,000) based on EPG. The EPG showed a negative correlation with both Hb and PCV (P < 0.01). Therefore, it was concluded that the Hb and PCV value would decrease, if EPG increases.

In vitro evaluation of osteoblast responses to carbon nanotube-coated titanium surfaces.

BACKGROUND: The effects of surface roughness and carboxyl functionalization of multi-walled carbon nanotubes (MWCNTs) mixed with collagen coated onto titanium (Ti) substrates on MC3T3-E1 osteoblasts were evaluated. METHODS: The proliferation, differentiation, and matrix mineralization were investigated using (1) smooth-surfaced Ti discs, (2) Ti discs coated with collagen and MWCNT (Ti-MWCNT), and (3) Ti discs coated with collagen and MWCNT-COOH (Ti-MWCNT-COOH) for applications in orthodontic mini screw implants (MSIs). The coatings were uniform when analyzed using scanning electron microscopy (SEM), and surface roughness was evaluated by surface profilometry that demonstrated similar surface roughness (R a , mean ± SD) in the MWCNT (0.83 ± 0.02 µm) and MWCNT-COOH (0.84 ± 0.01 µm) groups. MTT (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide) assay was performed after days 1, 3, and 7 to assess proliferation. Alkaline phosphatase (ALP)-specific activity was assessed after day 7 to quantify differentiation. Alizarin red staining was measured after day 28 to quantify matrix mineralization. All data were analyzed with JMP Pro11 software (SAS, USA) with a statistical significance of p < 0.05. RESULTS: Surface profilometry demonstrated similar surface roughness (R a , mean ± SD) in the MWCNT (0.83 ± 0.02 µm) and MWCNT-COOH (0.84 ± 0.01 µm) groups. On day 7, ALP assay showed that MWCNT-COOH (mean ± SD 0.98 ± 0.26 U/µg of protein) enhanced cell differentiation when compared to the uncoated group (p = 0.05). Alizarin red staining after 28 days of cell culture revealed that MWCNT-COOH (mean ± SD 1.5 ± 0.2 OD405) increased (p = 0.03) matrix mineralization when compared to the uncoated group (0.9 ± 0.09 OD405). CONCLUSIONS: This study showed that coatings containing MWCNT-COOH (increased hydrophilic surface chemistry) influence osteoblast proliferation, differentiation, and matrix mineralization and should be further studied for applications in orthodontic MSIs.

Status of benzimidazole resistance in Haemonchus contortus of goats from different geographic regions of Uttar Pradesh, India.

Present study was designed to survey the status of benzimidazole (BZ) resistance in goat flocks of different agro climatic regions of Uttar Pradesh (U.P.), India by faecal egg count reduction test (FECRT) and allele specific PCR (AS-PCR). Faecal egg counts and larval culture were made from representative samples of all regions. The results of the faecal culture and PCR-RFLP on beta tubulin isotype-1 gene showed Haemonchus contortus was predominant species. FECRT results showed BZ resistance prevalent in all regions. However, six farms of twenty screened, harboured susceptible populations of strongyles. Three hundred H. contortus infective larvae from all regions of the state were genotyped for BZ resistance. AS-PCR results revealed 55-85% of H. contortus homozygous resistant (rr), 10-21% homozygous susceptible (SS) and 5-24% heterozygous (rS) among different regions of U.P. The allele frequencies were 67-87.5% for resistant (TTC) and 12.5-33% for susceptible (TAC). The survey indicated that the status of BZ resistance is in alarming conditions in all the parts of the state.

Ab initio molecular orbital and density functional studies on the ring-opening reaction of oxetene.

Electrocyclic ring opening (ERO) reaction of 2H-Oxete (oxetene) has been carried out computationally in the gas phase and ring opening barrier has been computed. When comparing the ERO reaction of oxetene with the parent hydrocarbon (cyclobutene), the ring opening of cyclobutene is found to exhibit pericyclic behavior while oxetene shows mild pseudopericyclic nature. Computation of the nucleus-independent chemical shift (NICS) of oxetene adds evidence for pseudopericyclic behavior of oxetene. By locking of lone pair of electrons by hydrogen bonding, it is seen that the pseudopericyclic nature of the ring opening of oxetene is converted into a pericyclic one. CASSCF(5,6)/6-311+G** computation was carried out to understand the extent of involvement of lone pair of electrons during the course of the reaction. CR-CCSD(T)/6-311+G** computation was performed to assess the energies of the reactant, transition state and the product more accurately.

Manganese hexacyanoferrate derived Mn3O4 nanocubes-reduced graphene oxide nanocomposites and their charge storage characteristics in supercapacitors.

Mn3O4-reduced graphene oxide (RGO) nanocomposites were prepared by chemical decomposition of the manganese hexacyanoferrate (MnHCF) complex directly on the graphene surface. XRD studies revealed the formation of crystalline hausmannite Mn3O4 nanocubes in the as-prepared nanocomposites without any heat treatment. The FE-SEM images showed the formation of Mn3O4 nanocubes on the graphene surface in the as-prepared nanocomposites. HR-TEM studies confirmed the homogeneous dispersion of ∼25 nm Mn3O4 nanocubes on graphene nanosheets. The amount of Mn3O4 nanocubes and graphene in the nanocomposites was estimated using TGA analysis from room temperature to 800 °C in air. The FT-IR and Raman spectroscopic analysis confirmed the functional groups in the nanocomposites and defects in graphene nanosheets in the nanocomposites. Cyclic voltammetry and galvanostatic charge-discharge experiments demonstrated a high specific capacitance of 131 F g(-1) in 1 M Na2SO4 electrolyte at a current density of 0.5 A g(-1) for the RGM-0.5 nanocomposite. A capacitance retention of 99% was observed for 500 charge-discharge cycles at a current density of 5 A g(-1), which conformed the excellent stability of the RGM electrodes. The prepared Mn3O4-RGO nanocomposites are promising for electrochemical energy storage.

Familial hypercholesterolaemia presenting with coronary artery disease in a young patient.

A man in his early 20s presented with an angina on exertion and postprandial angina. Upon examination, the patient had carotid artery bruit and multiple tendon xanthomas. His lipid profile showed a very high total and low-density lipoprotein cholesterol; treadmill test was strongly positive. Subsequent coronary angiogram revealed triple vessel disease. The patient underwent revascularisation and is on lipid lowering therapy.

Biodegradation, soft and hard tissue integration of various polyethylene glycol hydrogels: a histomorphometric study in rabbits.

OBJECTIVES: (i) To evaluate biodegradation, hard and soft tissue integration using various polyethylene glycol (PEG) hydrogels; (ii) to evaluate the influence of arginine-glycine-aspartic acid (RGD) on two types of PEG hydrogels. MATERIAL AND METHODS: In seven rabbits, six treatment modalities were randomly applied subperiosteally on the skull: (1) a dense network PEG hydrogel (PEG1), (2) PEG1 modified with RGD (PEG1-RGD), (3) a looser network PEG hydrogel (PEG2), (4) PEG2 modified with RGD (PEG2-RGD), (5) a collagen membrane, and (6) a polylactide/polyglycolide/trimethylene carbonate membrane. The animals were sacrificed at 14 days. Histomorphometric analyses were performed on undecalcified Epon sections using a standardized region of interest. For statistical analysis, paired t-test and signed rank test were applied. RESULTS: PEG1 and PEG1-RGD remained intact and maintained the shape. PEG2 and PEG2-RGD completely degraded and were replaced by connective tissue and bone. The largest amount of mineralized tissue was found for PEG2-RGD (21.4%), followed by PEG 2 (9.5%). The highest percentage of residual hydrogel/membrane was observed for PEG1-RGD (55.6%), followed by PEG1 (26.7%). CONCLUSIONS: Modifications of the physico-chemical properties of PEG hydrogels and the addition of RGD influenced soft and hard tissue integration and biodegradation. PEG1 showed an increased degradation time and maintained the shape. The soft tissue integration was enhanced by adding an RGD sequence. A high turn-over rate and extensive bone regeneration was observed using PEG2. The addition of RGD further improved bone formation and soft tissue integration.

Serological evidence for wide distribution of spotted fevers & typhus fever in Tamil Nadu.

BACKGROUND & OBJECTIVE: Although the re-emergence of spotted fevers and typhus was documented from southern India a few years ago, there was a paucity of community based data. Therefore a collaborative study was carried out in several districts of Tamil Nadu to understand the distribution of these infections. METHODS: Blood (3 ml) was collected from patients presenting to primary health centres (PHCs) with fever >10 days duration in 15 districts of Tamil Nadu during January 2004 to December 2005. Patients negative for malaria, were tested by Weil-Felix test. Clinical data were collected from patients visiting two hospitals. RESULTS: A total 306 samples were tested in 2004 and 115 (37.5%) had titres of >or=80 with OX K antigen, suggesting a diagnosis of scrub typhus. During 2005, 964 patients were tested and 89 (9.2%) were positive for scrub typhus. An additional 44 (4.6%) were positive for other rickettsial illnesses. In both years majority of scrub typhus occurred in individuals above 14 yr of age. Cases increased from August until the earlier part of next year. INTERPRETATION & CONCLUSION: This community based study from south India involving several districts in Tamil Nadu, showed that scrub typhus and rickettsial illnesses were widely distributed in the State. Measures to increase awareness and also to diagnose and treat this infection in the affected areas are essential.

Fabrication of poly(ethylene glycol) hydrogel micropatterns with osteoinductive growth factors and evaluation of the effects on osteoblast activity and function.

The aims of this study were to fabricate poly(ethylene glycol) (PEG) hydrogel micropatterns on a biomaterial surface to guide osteoblast behaviour and to study how incorporating vascular endothelial growth factor (VEGF) within the adhered hydrogel influenced cell morphology. Standard photolithographic procedures or photopolymerization through a poly(dimethyl siloxane) (PDMS) mould were used to fabricate patterned PEG hydrogels on the surface of silanized silicon wafers. Hydrogel patterns were evaluated by light microscopy and surface profilometry. Rat osteoblasts were cultured on these surfaces and cell morphology investigated by fluorescence microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Release of protein trapped in the polymerized PEG was evaluated and VEGF-PEG surfaces were characterized for their ability to support cell growth. These studies show that photopolymerized PEG can be used to create anti-adhesive structures on the surface of silicon that completely control where cell interaction with the substrate takes place. Using conventional lithography, structures down to 50 microm were routinely fabricated with the boundaries exhibiting sloping sides. Using the PDMS mould approach, structures were fabricated as small as 10 microm and boundaries were very sharp and vertical. Osteoblasts exhibiting typical morphology only grew on the silicon wafer surface that was not coated with PEG. Adding BSA to the monomer solution showed that protein could be released from the hydrogel for up to 7 days in vitro. Incorporating VEGF in the hydrogel produced micropatterns that dramatically altered osteoblast behaviour. At boundaries with the VEGF-PEG hydrogel, there was striking formation of cellular processes and membrane ruffling indicative of a change in cell morphology. This study has explored the morphogenetic properties of VEGF and the applications of nano/microfabrication techniques for guided tissue (bone) regeneration in dental and orthopaedic applications using osteoinductive PEG hydrogel micropatterns.