Cleanroom-Free Direct Laser Micropatterning of Polymers for Organic Electrochemical Transistors in Logic Circuits and Glucose Biosensors

Organic electrochemical transistors (OECTs) are promising devices for bioelectronics, such as biosensors. However, current cleanroom-based microfabrication of OECTs hinders fast prototyping and widespread adoption of this technology for low-volume, low-cost applications. To address this limitation, a versatile and scalable approach for ultrafast laser microfabrication of OECTs is herein reported, where a femtosecond laser to pattern insulating polymers (such as parylene C or polyimide) is first used, exposing the underlying metal electrodes serving as transistor terminals (source, drain, or gate). After the first patterning step, conducting polymers, such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), or semiconducting polymers, are spin-coated on the device surface. Another femtosecond laser patterning step subsequently defines the active polymer area contributing to the OECT performance by disconnecting the channel and gate from the surrounding spin-coated film. The effective OECT width can be defined with high resolution (down to 2 µm) in less than a second of exposure. Micropatterning the OECT channel area significantly improved the transistor switching performance in the case of PEDOT:PSS-based transistors, speeding up the devices by two orders of magnitude. The utility of this OECT manufacturing approach is demonstrated by fabricating complementary logic (inverters) and glucose biosensors, thereby showing its potential to accelerate OECT research.

Corrigendum to "Probabilistic cell seeding and non-autofluorescent 3D-printed structures as scalable approach for multi-level co-culture modeling" [Mater. Today Bio 21, August 2023, 100706]

[This corrects the article DOI: 10.1016/j.mtbio.2023.100706.].

Probabilistic cell seeding and non-autofluorescent 3D-printed structures as scalable approach for multi-level co-culture modeling

To model complex biological tissue in vitro, a specific layout for the position and numbers of each cell type is necessary. Establishing such a layout requires manual cell placement in three dimensions (3D) with micrometric precision, which is complicated and time-consuming. Moreover, 3D printed materials used in compartmentalized microfluidic models are opaque or autofluorescent, hindering parallel optical readout and forcing serial characterization methods, such as patch-clamp probing. To address these limitations, we introduce a multi-level co-culture model realized using a parallel cell seeding strategy of human neurons and astrocytes on 3D structures printed with a commercially available non-autofluorescent resin at micrometer resolution. Using a two-step strategy based on probabilistic cell seeding, we demonstrate a human neuronal monoculture that forms networks on the 3D printed structure and can establish cell-projection contacts with an astrocytic-neuronal co-culture seeded on the glass substrate. The transparent and non-autofluorescent printed platform allows fluorescence-based immunocytochemistry and calcium imaging. This approach provides facile multi-level compartmentalization of different cell types and routes for pre-designed cell projection contacts, instrumental in studying complex tissue, such as the human brain.

Astrocyte 3D culture and bioprinting using peptide functionalized hyaluronan hydrogels

Astrocytes play an important role in the central nervous system, contributing to the development of and maintenance of synapses, recycling of neurotransmitters, and the integrity and function of the blood-brain barrier. Astrocytes are also linked to the pathophysiology of various neurodegenerative diseases. Astrocyte function and organization are tightly regulated by interactions mediated by the extracellular matrix (ECM). Engineered hydrogels can mimic key aspects of the ECM and can allow for systematic studies of ECM-related factors that govern astrocyte behaviour. In this study, we explore the interactions between neuroblastoma (SH-SY5Y) and glioblastoma (U87) cell lines and human fetal primary astrocytes (FPA) with a modular hyaluronan-based hydrogel system. Morphological analysis reveals that FPA have a higher degree of interactions with the hyaluronan-based gels compared to the cell lines. This interaction is enhanced by conjugation of cell-adhesion peptides (cRGD and IKVAV) to the hyaluronan backbone. These effects are retained and pronounced in 3D bioprinted structures. Bioprinted FPA using cRGD functionalized hyaluronan show extensive and defined protrusions and multiple connections between neighboring cells. Possibilities to tailor and optimize astrocyte-compatible ECM-mimicking hydrogels that can be processed by means of additive biofabrication can facilitate the development of advanced tissue and disease models of the central nervous system.

Rapid prototyping of heterostructured organic microelectronics using wax printing, filtration, and transfer

Conducting polymers are the natural choice for soft electronics. However, the main challenge is to pattern conducting polymers using a simple and rapid method to manufacture advanced devices. Filtration of conducting particle dispersions using a patterned membrane is a promising method. Here, we show the rapid prototyping of various micropatterned organic electronic heterostructures of PEDOT:PSS by inducing the formation of microscopic hydrogels, which are then filtered through membranes containing printed hydrophobic wax micropatterns. The hydrogels are retained on the un-patterned, hydrophilic regions, forming micropatterns, achieving a resolution reaching 100 μm. We further solve the problem of forming stacked devices by transferring the acidified PEDOT:PSS micropattern using the adhesive tape transfer method to form vertical heterostructures with other micropatterned electronic colloids such as CNTs, which are patterned using a similar technique. We demonstrate a number of different heterostructure devices including micro supercapacitors and organic electrochemical transistors and also demonstrate the use of acidified PEDOT:PSS microstructures in cell cultures to enable bioelectronics.

Calcium-Mediated Liposome Fusion to Engineer Giant Lipid Vesicles with Cytosolic Proteins and Reconstituted Mammalian Proteins

Giant unilamellar lipid vesicles (GUVs) are widely used as model membrane systems and provide an excellent basis to construct artificial cells. To construct more sophisticated artificial cells, proteins-in particular membrane proteins-need to be incorporated in GUVs. However, current methods for protein reconstitution have limited throughput or are not generally applicable for all proteins because they depend on detergent solubilization. This limitation is addressed here by introducing calcium-mediated membrane fusion to transfer proteins between negatively charged GUVs and cell-derived plasma membrane vesicles (CDVs), derived from HEK293T cells overexpressing a membrane receptor protein. Fusion conditions are optimized using large unilamellar vesicles and GUVs containing phosphatidylserines and fusogenic lipids. The approach is then applied to induce lipid mixing and subsequent transfer of the overexpressed membrane receptor from CDVs into GUVs. The membrane receptor is detected by immunofluorescence on GUVs that underwent lipid mixing with CDVs. Those GUVs also exhibit esterase activity because cytosolic esterases entrapped in the CDVs are transferred during membrane fusion. Thus, content mixing is demonstrated. Using CDVs circumvents the need to purify or solubilize proteins. Moreover, calcium-mediated fusion allows transfer of lipids, water-soluble and membrane bound proteins in one step, resulting in a semi-synthetic cell.

3D-Printed Soft Lithography for Complex Compartmentalized Microfluidic Neural Devices

Compartmentalized microfluidic platforms are an invaluable tool in neuroscience research. However, harnessing the full potential of this technology remains hindered by the lack of a simple fabrication approach for the creation of intricate device architectures with high-aspect ratio features. Here, a hybrid additive manufacturing approach is presented for the fabrication of open-well compartmentalized neural devices that provides larger freedom of device design, removes the need for manual postprocessing, and allows an increase in the biocompatibility of the system. Suitability of the method for multimaterial integration allows to tailor the device architecture for the long-term maintenance of healthy human stem-cell derived neurons and astrocytes, spanning at least 40 days. Leveraging fast-prototyping capabilities at both micro and macroscale, a proof-of-principle human in vitro model of the nigrostriatal pathway is created. By presenting a route for novel materials and unique architectures in microfluidic systems, the method provides new possibilities in biological research beyond neuroscience applications.

[Surgical treatment of posterosuperior impingement (PSI)]

OBJECTIVE

To restore the physiologic anterior and posterior capsular volume to achieve an anatomic central contact point of the glenohumeral articulation and treatment of concomitant glenohumeral injuries due to posterosuperior impingement (PSI).

INDICATIONS

Plateauing of clinical improvement despite adequate nonsurgical treatment (for at least 6-12 months).

CONTRAINDICATIONS

General contraindications for elective arthroscopic surgery.

SURGICAL TECHNIQUE

Diagnostic arthroscopy of the glenohumeral joint through the posterior portal to assess stability of the biceps-labral complex even in the Abduction and External Rotation (ABER) position to confirm the diagnosis of PSI and to detect concomitant glenohumeral injuries. In most cases posterosuperior SLAP (superior labrum anterior posterior) repair or tenodesis of the long head of the biceps.

POSTOPERATIVE MANAGEMENT

Arm sling for 6 weeks with limited range of motion. Free active range of motion of elbow and wrist. Limited shoulder external rotation for 6 weeks. Free shoulder range of motion from week 7, full daily life activities after 12 weeks. Modification of the postoperative management according to intraoperative findings.

RESULTS

At our hospital 18 overhead athletes (6 women, 12 men, mean age 31 years) with PSI without SLAP lesion or rotator cuff tear underwent isolated plication of the anteroinferior capsule after primary nonsurgical treatment. At a mean period of 9 months, 16 patients returned to their pre-injury sports activity level, 2 patients had to give up their sports due to persisting shoulder problems. At a mean follow-up of 27 months (range 12-55 months) the Walch Duplay score was on average 82.9 ± 8.3 for men and 73.8 ± 5.9 for women.

Stem cells and bFGF in tendon healing: Effects of lentiviral gene transfer and long-term follow-up in a rat Achilles tendon defect model

BACKGROUND

The influence of stem cells and lentiviral expression of basic fibroblastic growth factor (bFGF) on tendon healing and remodelling was investigated in an in-vivo long-term (12 weeks) rat Achilles tendon defect model.

METHODS

In sixty male Lewis rats, complete tendon defects (2.4 mm) were created and either left untreated (PBS) or treated by injection of stem cells lentivirally expressing the enhanced green fluorescence marker gene eGFP (MSC-LV-eGFP) or basic fibroblast growth factor bFGF (MSC-LV-bFGF). Tendons were harvested after 12 weeks and underwent biomechanical and (immuno)-histological analysis.

RESULTS

After 12 weeks the mean ultimate load to failure ratio (treated side to contralateral side) in biomechanical testing reached 97 % in the bFGF-group, 103 % in the eGFP-group and 112 % in the PBS-group. Also in the stiffness testing both MSC groups did not reach the results of the PBS group. Histologically, the MSC groups did not show better results than the control group. There were clusters of ossifications found in all groups. In immunohistology, only the staining collagen-type-I was strongly increased in both MSC groups in comparison to PBS control group. However, there were no significant differences in the (immuno)-histological results between both stem cell groups.

CONCLUSION

The biomechanical and (immuno)-histological results did not show positive effects of the MSC groups on tendon remodelling in a long-term follow-up. Interestingly, in later stages stem cells had hardly any effects on biomechanical results. This study inspires a critical and reflected use of stem cells in tendon healing.

Stem cells and basic fibroblast growth factor failed to improve tendon healing: an in vivo study using lentiviral gene transfer in a rat model

BACKGROUND

The aim of this controlled study was to investigate the influence of mesenchymal stem cells (MSCs) and lentiviral (LV) expression of basic fibroblast growth factor (bFGF) on tendon remodeling in an in vivo rat model of an Achilles tendon defect.

METHODS

In eighty-four male Lewis rats, complete 2.4-mm tendon defects were created and were either left untreated (the phosphate-buffered saline solution [PBS] group) or were treated with mesenchymal stem cells expressing enhanced green fluorescent protein (the MSC-LV-eGFP group) or with mesenchymal stem cells expressing basic fibroblast growth factor lentivirally (the MSC-LV-bFGF group). After fourteen and twenty-eight days, the tendons were harvested and analyzed biomechanically and immunohistologically.

RESULTS

After fourteen days, both mesenchymal stem cell groups were slightly superior in biomechanical testing. However, only the PBS control group showed a significant increase in biomechanical results over time (fourteen versus twenty-eight days; p = 0.012). Biomechanical results were better after twenty-eight days for the control group than for both MSC groups. However, the difference was significant only with regard to the stiffness results in the comparison of the PBS control and the eGFP stem cell group (p = 0.024). Histologically, the MSC groups had no better results than the control group after fourteen and twenty-eight days. In immunohistology, only labeling for type-I procollagen was strongly increased in both MSC groups in comparison with the PBS control group (p = 0.0009 for the MSC-LV-bFGF group and p = 0.0041 for the MSC-LV-eGFP group at fourteen days, and p = 0.004 and p = 0.132, respectively, at twenty-eight days). There were no significant differences in the immunohistological results between the stem cell groups.

CONCLUSIONS

The biomechanical and immunohistological results showed that mesenchymal stem cells in both groups had only partially positive effects on tendon remodeling in the initial stages; however, in later stages, stem cells had potentially negative effects on biomechanical results. The additional expression of bFGF in stem cells had negligible effects on tendon remodeling.

CLINICAL RELEVANCE

Preliminary studies using stem cells are partially promising; however, there are no relevant clinical data showing that stem cells are of significant benefit. The present study should lead to a more critical evaluation and thoughtful use of stem cells in humans until more clinical data are available.

Clinical and structural evaluation of arthroscopic double-row suture-bridge rotator cuff repair: early results of a novel technique

PURPOSE

Assessment of repair integrity and clinical outcome after arthroscopic repair of rotator cuff tears in double-row suture-bridge technique with the use of a new knotless suture-anchor system.

METHODS

The first treated 25 patients with arthroscopic rotator cuff repair in the suture-bridge technique using a novel knotless anchor and chain-link suture system were evaluated. Patients with isolated full-thickness supraspinatus tears were selected. They were followed clinically with functional scores (Constant score, ASES index), visual analog scale (VAS), and instrumentally with Isobex digital strength analyzer preoperatively, at 6 and 14 months postoperatively. The repair integrity was evaluated with MRI at an average of 14 months postoperatively.

RESULTS

Significant improvement of pain, strength, range of motion, and functional scores occurred (P < 0.05). There was a re-tear rate of 20%. The subjective parameters (VAS and ASES Index) showed non-significant (n.s.) differences between the re-tear and intact repair groups, whereas the objective parameters (Constant score, muscle power and active ROM) showed significant differences between both groups (P < 0.05).

CONCLUSION

The functional outcome has improved significantly with this new knotless anchor-chain system and was more superior in shoulders with intact repair, whereas the resulted repair integrity was not better than other types of double-row repair techniques mentioned in the recent literature. However, this early report of the novel technique may show limited power for comparison due to the relatively small sample size.

[Allografts for cruciate ligament reconstruction]

Allografts have an essential significance in the surgical reconstruction of ligamentous injuries around the knee joint. While in primary anterior cruciate ligament reconstruction allografts are less important than autografts, at least in the European countries, the usage of allografts in anterior cruciate ligament revision surgery is increasing. In addition, allografts represent a good alternative for the reconstruction of the posterior cruciate ligament and the posterolateral structures. Especially in multiligament reconstructions of the knee joint, the usage of allografts may prevent iatrogenic damage of the already traumatized periarticular soft tissue. The present article focuses on the application and clinical results of allografts for ligament reconstruction around the knee joint. Furthermore, the immunological and biological principles of tendon allografts, their availability, processing, and security are discussed.

Ciprokiren (Ro 44-9375). A renin inhibitor with increasing effects on chronic treatment

The present study characterizes the new transition-state renin inhibitor ciprokiren (Ro 44-9375) in squirrel monkeys. Arterial blood pressure was monitored by telemetry in freely moving, chronically instrumented conscious animals. In vitro at pH 7.4, ciprokiren inhibited human renin in buffer and human plasma with an IC50 of 0.07 and 0.65 nmol/L, respectively. It was equipotent against primate plasma renin and also inhibited plasma renin from dog and guinea pig in the nanomolar range (IC50, 29 and 65 nmol/L, respectively). After acute oral administration it reduced arterial blood pressure dose dependently in normotensive sodium-depleted and cyclosporin-induced hypertensive squirrel monkeys, starting with the minimal oral dose of 3 micrograms/kg. Daily oral doses of 1 microgram/kg showed a progressive blood pressure decrease, with a maximal response reached after 1 week. The drug could also be applied transdermally with similar hemodynamic effects without any decrease of plasma renin activity or plasma immunoreactive angiotensin II. Thus, ciprokiren is characterized in squirrel monkeys as a renin inhibitor with high in vivo potency that might act mainly in the tissular compartment.

[Vitamin K deficiency with erythromycin. Observation of a boy treated with valproate]

A nine year old boy had been treated with valproic acid during one and a half years because of a grand mal epilepsy. Under an additional medication with erythromycin succinate syrup this patient developed a deficiency of prothrombin-complex, which was reversible immediately after oral intake of vitamin K. In this case it is assumed that the simultaneous application of both valproic acid and erythromycin succinate seems to suppress the vitamin K producing intestinal tract bacteria, which has not been reported in the literature so far.

[Homozygous infant in a family with hereditary protein C deficiency]

We report on a female infant homozygous for protein C deficiency in a Jordanian family with frequent intermarriage. A protein C antigen of 0.6% was determined. The parents first noticed painful nodular indurations in subcutanous tissue as well as blue-red skin coloration at the age of 6 months. The girl repeatedly suffered from microthrombotic events in parts of the body with large areas of subcutaneous fat. In contrast, the numerous heterozygous carriers with partial protein C deficiency did not show an increased tendency to thrombosis. From the history an autosomal-recessive inheritance may be inferred. Other authors reporting on homozygous cases also postulate the presence of a recessive gene. It is of interest that the infant described here differs from those in other case reports in the age at manifestation of the disease. The homozygous infant showed the first symptoms as late as the age of 6 months, whereas other case reports describe severe symptoms immediately after birth. All symptoms of disease were treated successfully with prothrombin complex concentrate without additional heparin protection. Microthrombotic events subsided quickly, and a large ulcer in the left flank healed almost completely within 6 days.

Aggressive combination chemotherapy of bone marrow relapse in childhood acute lymphoblastic leukemia containing aclacinomycin-A: a multicentric trial

An intensive 7-day combination chemotherapy protocol was designed to reinduce children with early bone marrow relapse of acute lymphoblastic leukemia (less than 6 months after the end of or during preceding treatment). This aggressive approach seemed to be justified for a group of patients who were at the highest risk for ultimate treatment failure. In all, 38 children were enrolled for study. The ratio of male (median age, 10 years) to female (median age, 13 years) subjects was 27:11. Thirty patients were treated for their first relapse and eight for their second or subsequent relapse. Isolated bone marrow involvement was present in 24 cases. All patients had received heavy pretreatment including anthracyclines with cumulative doses of between 120 and 240 mg/m2. 22 of these patients, achieved complete remission, ten did not respond to therapy, and six died from the toxicity of the protocol. Cardiac failure was the cause of death in one child (after additional radiotherapy for a mediastinal mass). No further clinical manifestation of cardiomyopathy could be observed. The other five patients died from hemorrhages or infectious complications. The main side effects were fever, gastrointestinal problems, stomatitis, and severe bone marrow aplasia lasting for about 2 weeks with nadirs of platelets and white blood count around days 10-14. The remission rate of 60% was acceptable, though not satisfactory. Only four children survived disease-free for 13+, 14+, 20+, and 22+ months after diagnosis of relapse.

[Successful chemotherapy in a primary cerebral centroblastic non-Hodgkin's lymphoma in childhood]

Primary lymphomas of the central nervous system (CNS) are rare diseases. Often these tumors are surrounded by glia cells and may, therefore, be misdiagnosed as 'astrocytomas' with accompanying reactive lymphocytosis. A 15-year old patient was irradiated to the posterior cranial fossa and the brain stem because of a supposed astrocytoma. Five months after completion of radiotherapy he presented two lesions each in the right and left cerebral hemisphere. Repeated biopsy led to a revision of the primary diagnosis in favor of a B-cell Non-Hodgkin lymphoma (centroblastic type). After cyclic polychemotherapy including high-dose methotrexate and cytosine-arabinoside he entered a complete remission. No further radiotherapy was given. So far, 18 months after discontinuating therapy, the patient has been in complete remission and is in an excellent physical condition.

[Malignant melanoma in the child--2 case reports]

Case histories of two infants with malignant melanoma are presented. Both tumors had developed from a congenital mole to advanced disease with lymph node metastasis at time of diagnosis, findings which are commonly correlated with poor outcome. Initially, both patients were surgically treated. From the experience with few described cases of melanoma in childhood and with a large number of adult patients, neither chemotherapy and conventional BCG immunotherapy nor irradiation seem to be an effective treatment and are accompanied by many adverse side effects. Therefore in one patient therapy was limited to surgery alone. In the other child it was followed by treatment with high-dose recombinant alpha-2-interferon (1 Mill. i.u./Kg X d) plus an H2-receptor antagonist. Unexpectedly this girl developed neurological side effects, characterized by spastic paraparesis, indicating damage to the first motoneuron. All symptoms completely resolved after discontinuation of drugs within three months. Both children have been in complete remission for 18+ and 32+ months, respectively.

[Biclonal leukemia O-ALL/AMoL) with 11;19 translocation and trisomy X in an 8-month-old girl]

Biclonal leukemia was diagnosed in an 8 months old girl, combining lymphoblastic (FAB L1) and monoblastic (FAB M 5) phenotypes which were classified as O-ALL and AMol by immunological examination of surface-antigens. Chemotherapy for one cell type resulted in predominance or relapse of the other one. Chromosomal abnormalities diagnosed in the lymphoblastic clone consisted of translocation t(11;19)(q23;p13) and triple X. The breakpoint 11q23 neighbouring one well known oncogene (ets) is not strictly associated with special leukemic phenotypes. But it is often found in infants and usually correlated with a poor prognosis. The data of 18 patients with hybrid leukemias registered in the BFM studies strongly support the fatal course of the disease. 12 months after diagnosis approximately 1 out of 10 children is expected to survive disease-free.

[Initial results of a study of the treatment of children with ALL recurrences]

Ninety-five children and adolescents with their first relapse of ALL were treated in the multicentric prospective trial ALL-REZ BFM 83. Treatment was stratified with respect to time and site of relapse. The overall remission rate was 86.3%. In the group of patients with early relapse only 44/56 children (78.6%) achieved a second remission, whereas the remission rate was 97.4% (38/39) in patients with late relapse. The 2 year probabilities of a sustained second complete remission are 0.65 +/- 0.10, 0.33 +/- 0.09 and 0.71 +/- 0.14 for patients with late, early and isolated CNS relapses, respectively. The poorest prognosis was observed in children with early marrow relapse (0.16 +/- 0.13 after one year).