Chemical Communication in Artificial Cells: Basic Concepts, Design and Challenges.

In the past decade, the focus of bottom-up synthetic biology has shifted from the design of complex artificial cell architectures to the design of interactions between artificial cells mediated by physical and chemical cues. Engineering communication between artificial cells is crucial for the realization of coordinated dynamic behaviours in artificial cell populations, which would have implications for biotechnology, advanced colloidal materials and regenerative medicine. In this review, we focus our discussion on molecular communication between artificial cells. We cover basic concepts such as the importance of compartmentalization, the metabolic machinery driving signaling across cell boundaries and the different modes of communication used. The various studies in artificial cell signaling have been classified based on the distance between sender and receiver cells, just like in biology into autocrine, juxtacrine, paracrine and endocrine signaling. Emerging tools available for the design of dynamic and adaptive signaling are highlighted and some recent advances of signaling-enabled collective behaviours, such as quorum sensing, travelling pulses and predator-prey behaviour, are also discussed.

Chemical-mediated translocation in protocell-based microactuators.

Artificial cell-like communities participate in diverse modes of chemical interaction but exhibit minimal interfacing with their local environment. Here we develop an interactive microsystem based on the immobilization of a population of enzyme-active semipermeable proteinosomes within a helical hydrogel filament to implement signal-induced movement. We attach large single-polynucleotide/peptide microcapsules at one or both ends of the helical protocell filament to produce free-standing soft microactuators that sense and process chemical signals to perform mechanical work. Different modes of translocation are achieved by synergistic or antagonistic enzyme reactions located within the helical connector or inside the attached microcapsule loads. Mounting the microactuators on a ratchet-like surface produces a directional push-pull movement. Our methodology opens up a route to protocell-based chemical systems capable of utilizing mechanical work and provides a step towards the engineering of soft microscale objects with increased levels of operational autonomy.

Catalytic processing in ruthenium-based polyoxometalate coacervate protocells.

The development of programmable microscale materials with cell-like functions, dynamics and collective behaviour is an important milestone in systems chemistry, soft matter bioengineering and synthetic protobiology. Here, polymer/nucleotide coacervate micro-droplets are reconfigured into membrane-bounded polyoxometalate coacervate vesicles (PCVs) in the presence of a bio-inspired Ru-based polyoxometalate catalyst to produce synzyme protocells (Ru4PCVs) with catalase-like activity. We exploit the synthetic protocells for the implementation of multi-compartmentalized cell-like models capable of collective synzyme-mediated buoyancy, parallel catalytic processing in individual horseradish peroxidase-containing Ru4PCVs, and chemical signalling in distributed or encapsulated multi-catalytic protocell communities. Our results highlight a new type of catalytic micro-compartment with multi-functional activity and provide a step towards the development of protocell reaction networks.

On-Site 4-in-1 Alignment: Visualization and Interactive CAD Model Retrofitting Using UAV, LiDAR's Point Cloud Data, and Video.

Acquisition of 3D point cloud data (PCD) using a laser scanner and aligning it with a video frame is a new approach that is efficient for retrofitting comprehensive objects in heavy pipeline industrial facilities. This work contributes a generic framework for interactive retrofitting in a virtual environment and an unmanned aerial vehicle (UAV)-based sensory setup design to acquire PCD. The framework adopts a 4-in-1 alignment using a point cloud registration algorithm for a pre-processed PCD alignment with the partial PCD, and frame-by-frame registration method for video alignment. This work also proposes a virtual interactive retrofitting framework that uses pre-defined 3D computer-aided design models (CAD) with a customized graphical user interface (GUI) and visualization of a 4-in-1 aligned video scene from a UAV camera in a desktop environment. Trials were carried out using the proposed framework in a real environment at a water treatment facility. A qualitative and quantitative study was conducted to evaluate the performance of the proposed generic framework from participants by adopting the appropriate questionnaire and retrofitting task-oriented experiment. Overall, it was found that the proposed framework could be a solution for interactive 3D CAD model retrofitting on a combination of UAV sensory setup-acquired PCD and real-time video from the camera in heavy industrial facilities.

Chloroplast-containing coacervate micro-droplets as a step towards photosynthetically active membrane-free protocells.

Encapsulation of structurally and functionally intact chloroplasts within coacervate micro-droplets is used to prepare membrane-free protocells capable of light-induced electron transport.

Simple and Facile Approach To Create Charge Reversible Pores via Hydrophobic Anchoring of Ionic Amphiphiles.

Mesoporous silica-based charge reversal systems have gained significant attention in recent years due to a variety of applications such as drug delivery, dye adsorption, catalysis, chromatography, etc. Such systems often use covalent strategies to immobilize functional groups on the silica scaffold. However, lack of dynamism, modularity, and postsynthetic flexibility associated with covalent routes limit their wider applicability. Alternatively, supramolecular routes are gaining increased attention owing to their ability to overcome these limitations. Here, we introduce a simple and facile noncovalent design for a highly reversible assembly of charged amphiphiles within mesopores. Hexyl pendant groups were covalently attached to the surface to provide hydrophobic anchoring for charged amphiphiles to enable facile switching of surface charge of the mesoporous silica. These charge-switchable surfaces were used for fast and selective adsorption of dyes from aqueous solutions.

Versatility of Pleuripotent Undifferentiated Stem Cells Aspirated from Bone Marrow and its Applications in Oral and Maxillofacial Surgery.

INTRODUCTION: Bone marrow (BM) derived pleuripotent undifferentiated stem cells represent a promising population for supporting new concepts in cellular therapy. AIM: The aim of this study is to evaluate the versatility of pleuripotent undifferentiated stem cells derived from BM aspiration and its applications in oral and maxillofacial surgical procedures. MATERIALS AND METHODS: A total of 30 patients out of which 15 were with hard tissue defects (cystic lesions n = 6, post surgical alveolar defects n = 4, peri implant defects n = 3, alveolar clefts n = 2) and 15 soft tissue lesions (leukoplakia and lichen planus n = 6, oral submucous fibrosis n = 7, post traumatic soft tissue loss n = 2) were included in the study on randomized clinical basis. The patients received autologous BM derived mononuclear cells which were being locally delivered into the lesion and followed up. The parameters used were (1) To compare and evaluate the bone regeneration by radiographic assessment at the end of 3rd and 6th month postoperatively. (2) Duration of the procedure. (3) Clinical improvement in the management of soft tissue lesions. (4) Assessment of wound healing by Vancouver burn scar assessment of wound. (5) Safety, postoperative infections and complications. RESULTS: For hard tissue lesions CT scans and OPG revealed adequate regenerated bone, bridging the defect after 3 months. Hounsfield units of regenerated bone after 6 months were more or less similar to native bone which was statistically significant (unpaired t test = p < 0.05). For soft tissue lesions (1) 7 cases of OSMF showed adequate clinical mouth opening (one way anova test = p < 0.05), reduction in burning sensation and blanching of mucosa, (2) 6 cases of leukoplakia and lichen planus and 2 cases of post traumatic soft tissue defects showed good clinical improvement by Vancouver burn scar assessment of wound index. CONCLUSION: The study shows that there is a definite beneficial effect in bone regeneration and soft tissue wound healing with the use of BM-derived mononuclear cells.

Reversible control of pore size and surface chemistry of mesoporous silica through dynamic covalent chemistry: philicity mediated catalysis.

Here, we report the synthesis of adaptive hybrid mesoporous silica having the ability to reconfigure its pore properties such as pore size and philicity in response to the external environment. Decyl chains were reversibly appended to the pore walls of silica through imine motifs as dynamic covalent modules to switch the pore size and philicity in response to pH. This switching of pore properties was used to gate the access of reactants to the gold nanoparticles immobilized inside the nanopores, thus enabling us to turn-on/turn-off the catalytic reaction. The use of such dynamic covalent modules to govern pore properties would enable the realization of intelligent hybrids capable of controlling many such chemical processes in response to stimuli.

Development and validation of a stability indicating RP-HPLC method for the determination of Rufinamide.

A stability-indicating RP-HPLC method was developed and validated for the determination of Rufinamide in tablet dosage forms using C 18 column (250 mm×4.6 mm, 5 µm) with mobile phase consisting of water-acetonitrile (40:60, v/v) with a flow rate of 0.8 mL/min (UV detection 215 nm). Linearity was observed over the concentration range 1.0-200 µg/mL (R2=0.9997) with regression equation y=113190 x+63053. Rufinamide was subjected to stress conditions including acidic, alkaline, oxidation, photolysis and thermal degradation. Rufinamide is more sensitive towards acidic degradation. The method was validated as per ICH guidelines.

A prospective study involving the use of platelet rich plasma in enhancing the uptake of bone grafts in the oral and maxillofacial region.

ABSTRACT: Platelet-rich plasma (PRP) is an autologous product that contains highly concentrated number of platelets in a small volume of plasma, derived from whole blood by gradient density centrifugation. It has been speculated that local growth factors in human platelets (insulin-like growth factor, IGF; transforming growth factor, TGF-ß; platelet derived growth factor, PDGF) would enhance healing of grafts and also counteract resorption. The aim of this study was to evaluate efficacy of PRP on early healing after autogenous bone grafting. Of the twenty patients selected ten were treated with autogenous bone graft and PRP (PRP group) and other ten with autogenous bone graft alone (non-PRP group). PRP group consisted of two benign tumor of mandible, one post surgical defect, two unilateral alveolar cleft, one bilateral alveolar cleft with skeletal class III malocclusion, one maxillary hypoplasia, one oronasal fistula, one recurrent tumor of mandible, one multiple impacted mandibular teeth. Non-PRP group consisted of seven benign tumor of jaw, one keratocyst odontogenic tumor, one orbital blow out fracture, one residual traumatic defect. Biopsies were taken in the native bone, PRP treated grafted bone, grafted bone without PRP at 3 months to assess the maturity of bone. Radiographic imaging was performed by panoramic radiography at 3 and 6 months to evaluate bone opacity of grafted bone on comparison with native bone and computerized tomography at 6 months to evaluate grafted bone morphologically and to measure bone density in Hounsfield units. Microscopic results showed that significantly more matured bone was formed at PRP treated sites as that of native bone and immature bone in controls after 3 months of healing. Bone opacity of PRP treated bone grafts was close to that of native bone than that of non-PRP treated bone grafts on panoramic radiograph at 3 and 6 months. There was graft loss in three cases and graft resorption in one case of non-PRP treated bone grafts at 6 months. In PRP group the compact bone was clearly differentiated from cancellous bone as in native bone and thick in five cases, thin in five cases. In non-PRP group the compact bone was thin as a whole. Comparing native bone group and PRP group the CT value of PRP treated bone graft was more or less close to native bone group and comparing native bone group and non-PRP group CT value was low in non-PRP treated bone graft. Whereas when comparing PRP and non-PRP group CT value was higher in PRP group. Autologous PRP was a safe, biocompatible, effective, source for growth factors and carries no risk of transmissible diseases. It enhances and accelerates bone regeneration of autogenous bone grafts.

Comparison of preauricular approach versus retromandibular approach in management of condylar fractures.

AIM: The aim of the study is to compare the two extra oral approaches to the TMJ viz preauricular and retromandibular approach in management of condylar fractures of mandible. METHODS AND MATERIALS: Patients with fractured dislocation and displacement of mandible condyle in medial direction were managed by preauricular approach. Patients with lateral displacement of mandibular condyle were managed by retromandibular approach. OPG, Reverse towne's, and C.T. scan were taken in all the cases prior to surgery to assess the pattern of displacement. RESULTS: In our study both approaches have given excellent access and visibility to the condylar fractures but with limitations in each technique. Minimal intraoperative and postoperative complications were encountered in both approaches. The duration of the procedure for preauricular approach was much longer when compared with retromandibular approach. Facial nerve weakness was common in patients treated with preauricular approach, which they improved over a period of time and had complete recovery. Postoperative scar was imperceptible in all cases and good cosmetic results were seen with both approaches. Mouth opening, mandibular movements and occlusion were more or less same in both the approaches while pain and clicking was common in preauricular approach. CONCLUSION: Both approaches have good results in managing condylar fractures with retromandibular approach having ease of access and ease of fixation. So one can always give preference to retromandibular approach over preauricular approach in managing the condylar fracture except in some cases where preauricular approach is the only option like anteromedial dislocation or complete medial dislocation of condylar segment. Situations, where patients who reported very late for the surgery with resultant scarring of the tissue, in those cases preauricular approach is the only option.