Pathways to tough yet soft materials

[Figure: see text].

4D-Printed Transformable Tube Array for High-Throughput 3D Cell Culture and Histology

3D cell cultures are rapidly emerging as a promising tool to model various human physiologies and pathologies by closely recapitulating key characteristics and functions of in vivo microenvironment. While high-throughput 3D culture is readily available using multi-well plates, assessing the internal microstructure of 3D cell cultures still remains extremely slow because of the manual, laborious, and time-consuming histological procedures. Here, a 4D-printed transformable tube array (TTA) using a shape-memory polymer that enables massively parallel histological analysis of 3D cultures is presented. The interconnected TTA can be programmed to be expanded by 3.6 times of its printed dimension to match the size of a multi-well plate, with the ability to restore its original dimension for transferring all cultures to a histology cassette in order. Being compatible with microtome sectioning, the TTA allows for parallel histology processing for the entire samples cultured in a multi-well plate. The test result with human neural progenitor cell spheroids suggests a remarkable reduction in histology processing time by an order of magnitude. High-throughput analysis of 3D cultures enabled by this TTA has great potential to further accelerate innovations in various 3D culture applications such as high-throughput/content screening, drug discovery, disease modeling, and personalized medicine.

Deletions in the SMN and NAIP genes in patients with spinal muscular atrophy in Croatia

Two genes, i.e. survival motor neuron (SMN) and neuronal apoptosis inhibitory protein (NAIP) have been mapped to the SMA region of chromosome 5q13. Both genes are frequently deleted or truncated in SMA patients. We have studied 26 patients with SMA types I-III, 29 first relatives, and 14 subjects with mild adult-onset type IV. DNA deletion genotypes were determined by PCR techniques amplifying exons 7 and 8 of SMN, and exon 5 of NAIP gene which distinguish SMN and NAIP telomeric copy from a non-pathogenic gene homologue as a centromeric copy. Results revealed the homozygous deletions of exon 7 and 8 of the SMN gene and exon 5 of the NAIP gene in 3/3 infants with SMA I and in 1/20 with SMA type II. Exons 7 and 8 of the SMN gene were homozygously deleted in 10/20 and only exon 7 in 6/20 children with SMA type II. The overall percentage of deletion cases observed was 77% in children with SMA types I-III. Adult patients with type IV SMA showed no homozygous deletion of exons 7, 8 and 5 of the SMN and NAIP genes. Also, all relatives had both a telomeric and centromeric SMN and NAIP copy. Deletion analysis of SMN and NAIP genes are a significant diagnostic tool, because there are clinical entities resembling SMA which most likely have another pathogenetic background.