NOVELTY - An amphiphilic peptide and/or peptoidcapable of forming a hydrogel, is new. The amphiphilic peptide and/or peptoid comprises (a) an amphiphilic sequence consisting a hydrophobic sequence stretch of n aliphatic amino acids, where n is 2-15, and (b) hydrophilic sequence stretch linked to the hydrophobic sequence stretch and having a polar moiety which is acidic, neutral or basic, where the polar moiety comprises m adjacent hydrophilic amino acids and m is 1-5.    USE - The amphiphilic peptide and/or peptoid are useful for preparing hydrogel and composition. The hydrogel is used for preparing peptide and/or peptoid scaffold used in surgical implant or stent, for releasing pharmaceutically active compound, and in fuel cell, solar cell, electronic cell, biosensing device, medical device, implant, pharmaceutical, cosmetic, tissue regeneration, stem cell therapy and gene therapy. The composition is useful in pharmaceutical, cosmetic composition, biomedical device and/or electronic device (all claimed). The prepared scaffold is useful for repair and replacement of tissues. The hydrogel can also be used for inter alia cell culture, and in tissue engineering, drug delivery and wound cover (gauze or sheet) for maintaining wound in a moist state for promoting healing of wound.    ADVANTAGE - The hydrogel is stable and has higher mechanical strength than collagen or its hydrolyzed form (gelatin). The hydrogel is rigid, biocompatible, non-toxic, cost effective and suitable to be used in electronic devices, entraps 99.9% water, can be prepared easily, and causes little side effects when used in vivo.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) hydrogel comprising the amphiphilic peptide and/or peptoid;    (2) method (M1) of preparing the hydrogel, involves dissolving the amphiphilic peptide and/or peptoid in an aqueous solution;    (3) surgical implant or stent comprising a peptide and/or peptoid scaffold, where the peptide and/or peptoid scaffold is formed by the hydrogel;    (4) pharmaceutical, cosmetic composition, biomedical device and/or electronic device comprising the amphiphilic peptide and/or peptoid;    (5) kit comprising a first container with the amphiphilic peptide and/or peptoid and a second container with an aqueous solution; and    (6) method (M2) of tissue regeneration, involves (a) providing the hydrogel, (b) exposing the hydrogel to cells which are to form regenerated tissue, and (c) allowing the cells to grow on the hydrogel.