Protocell Flow Reactors for Enzyme and Whole-Cell Mediated Biocatalysis.

The design and construction of continuous flow biochemical reactors comprising immobilized biocatalysts have generated great interest in the efficient synthesis of value-added chemicals. Living cells use compartmentalization and reaction-diffusion processes for spatiotemporal regulation of biocatalytic reactions, and implementing these strategies into continuous flow reactors can offer new opportunities in reactor design and application. Herein, the fabrication of protocell-based continuous flow reactors for enzyme and whole-cell mediated biocatalysis is demonstrated. Semipermeable membranized coacervate vesicles are employed as model protocells that spontaneously sequester enzymes or accumulate living bacteria to produce embodied microreactors capable of single- or multiple-step catalytic reactions. By packing millions of the enzyme/bacteria-containing coacervate vesicles in a glass column, a facile, cost-effective, and modular methodology capable of performing oxidoreductase, peroxidase and lipolytic reactions, enzyme-mediated L-DOPA synthesis, and whole-cell glycolysis under continuous flow conditions, is demonstrated. It is shown that the protocell-nested enzymes and bacterial cells exhibit enhanced activities and stability under deleterious operating conditions compared with their non-encapsulated counterparts. These results provide a step toward the engineering of continuous flow reactors based on cell-like microscale agents and offer opportunities in the development of green and sustainable industrial bioprocessing.

Enzymatic Reaction-Coupled, Cooperative Supramolecular Polymerization.

Nature employs sophisticated mechanisms to precisely regulate self-assembly and functions within biological systems, exemplified by the formation of cytoskeletal filaments. Various enzymatic reactions and auxiliary proteins couple with the self-assembly process, meticulously regulating the length and functions of resulting macromolecular structures. In this context, we present a bioinspired, reaction-coupled approach for the controlled supramolecular polymerization in synthetic systems. To achieve this, we employ an enzymatic reaction that interfaces with the adenosine triphosphate (ATP)-templated supramolecular polymerization of naphthalene diimide monomers (NSG). Notably, the enzymatic production of ATP (template) plays a pivotal role in facilitating reaction-controlled, cooperative growth of the NSG monomers. This growth process, in turn, provides positive feedback to the enzymatic production of ATP, creating an ideal reaction-coupled assembly process. The success of this approach is further evident in the living-growth characteristic observed during seeding experiments, marking this method as the pioneering instance where reaction-coupled self-assembly precisely controls the growth kinetics and structural aspects of supramolecular polymers in a predictive manner, akin to biological systems.

ATP-Driven Synthetic Supramolecular Assemblies: From ATP as a Template to Fuel.

Adenosine triphosphate (ATP) is a molecular unit of energy that drives various processes in the cellular environment. In this Minireview, we discuss the potential of physical and chemical properties of ATP for the development of bio-inspired, synthetic ATP-induced supramolecular systems with dynamic, stimuli-responsive and active assembly characteristics. Molecular design rules for ATP-induced assemblies with various architectures and their stimuli-responsive structural and functional response are categorized. Special attention is given to the immense potential of ATP-fuelled designs in the nascent field of transient/non-equilibrium supramolecular polymerization for the synthesis of lifelike temporally programmable soft materials. Finally, the existing dearth and fate of ATP-driven systems for future challenges are discussed.

Bioinspired, ATP-driven co-operative supramolecular polymerization and its pathway dependence.

A bio-inspired, ATP-driven nucleation growth assembly is demonstrated using an amphiphilic naphthalene diimide (NDI) derivative appended with guanidinium receptors to promote specific salt-bridge type interaction with nucleotide phosphates. Detailed spectroscopic and microscopic probing revealed a pathway-dependent co-operative self-assembly to yield two-dimensional and scrolled nano-tubular bilayer assemblies under kinetic and thermodynamic conditions, respectively.

A health care labyrinth: perspectives of caregivers on the journey to accessing timely cancer diagnosis and treatment for children in India.

BACKGROUND: Cure rates for children with cancer in India lag behind that of high-income countries. Various disease, treatment and socio-economic related factors contribute to this gap including barriers in timely access of diagnostic and therapeutic care. This study investigated barriers to accessing care from symptom onset to beginning of treatment, from perspectives of caregivers of children with cancer in India. METHODS: Semi-structured in-depth interviews were conducted with caregivers of children (< 18 years) diagnosed with cancer in seven tertiary care hospitals across New Delhi and Hyderabad. Purposive sampling to saturation was used to ensure adequate representation of the child's gender, age, cancer type, geographical location and socioeconomic status. Interviews were audio recorded after obtaining informed consent. Thematic content analysis was conducted and organised using NVivo 11. RESULTS: Thirty-nine caregivers were interviewed, where three key themes emerged from the narratives: time intervals to definitive diagnosis and treatment, the importance of social supportive care and the overall accumulative impacts of the journey. There were two phases encapsulating the experiences of the family: referral pathways taken to reach the hospital and after reaching the hospital. Most caregivers, especially those from distant geographical areas had variable and inconsistent referral pathways partly due to poor availability of specialist doctors and diagnostic facilities outside major cities, influence from family or friends, and long travel times. Upon reaching the hospital, families mostly from public hospitals faced challenges navigating the hospital facilities, finding accommodation, and comprehending the diagnosis and treatment pathway. Throughout both phases, financial constraint was a recurring issue amongst low-income families. The caregiver's knowledge and awareness of the disease and health system, religious and social factors were also common barriers. CONCLUSION: This qualitative study highlights and explores some of the barriers to childhood cancer care in India. Our findings show that referral pathways are intrinsically linked to the treatment experience and there should be better recognition of the financial and emotional challenges faced by the family that occur prior to definitive diagnosis and treatment. This information would help inform various stakeholders and contribute to improved interventions addressing these barriers.

Biomimetic temporal self-assembly via fuel-driven controlled supramolecular polymerization.

Temporal control of supramolecular assemblies to modulate the structural and transient characteristics of synthetic nanostructures is an active field of research within supramolecular chemistry. Molecular designs to attain temporal control have often taken inspiration from biological assemblies. One such assembly in Nature which has been studied extensively, for its well-defined structure and programmable self-assembly, is the ATP-driven seeded self-assembly of actin. Here we show, in a synthetic manifestation of actin self-assembly, an ATP-selective and ATP-fuelled, controlled supramolecular polymerization of a phosphate receptor functionalised monomer. It undergoes fuel-driven nucleation and seeded growth that provide length control and narrow dispersity of the resultant assemblies. Furthermore, coupling via ATP-hydrolysing enzymes yielded its transient characteristics. These results will usher investigations into synthetic analogues of important biological self-assembly motifs and will prove to be a significant advancement toward biomimetic temporally programmed materials.

The molecular recognition controlled stereomutation cycle in a dynamic helical assembly.

Perylene bisimide functionalized with a phosphate recognition unit assembles into a left-handed, right-handed or racemic helical assembly on binding with AMP, ATP and inorganic phosphates, respectively. Thus, competitive binding among these multivalent guests was utilized for completing an unprecedented helix mutation cycle in a dynamic supramolecular assembly.

Supply chain dynamics in healthcare services.

PURPOSE: The purpose of this paper is to analyse health service supply chain systems. A great deal of literature is available on supply chain management in finished goods inventory situations; however, little research exists on managing service capacity when finished goods inventories are absent. DESIGN/METHODOLOGY/APPROACH: System dynamics models for a typical service-oriented supply chain such as healthcare processes are developed, wherein three service stages are presented sequentially. FINDINGS: Just like supply chains with finished goods inventory, healthcare service supply chains also show dynamic behaviour. Comparing options, service reduction, and capacity adjustment delays showed that reducing capacity adjustment and service delays gives better results. RESEARCH LIMITATIONS/IMPLICATIONS: The study is confined to health service-oriented supply chains. Further work includes extending the study to service-oriented supply chains with parallel processing, i.e. having more than one stage to perform a similar operation and also to study the behaviour in service-oriented supply chains that have re-entrant orders and applications. Specific case studies can also be developed to reveal factors relevant to particular service-oriented supply chains. PRACTICAL IMPLICATIONS: The paper explains the bullwhip effect in healthcare service-oriented supply chains. Reducing stages and capacity adjustment are strategic options for service-oriented supply chains. ORIGINALITY/VALUE: The paper throws light on policy options for managing healthcare service-oriented supply chain dynamics.