I dagsläget utvecklas ständigt nya läkemedel med hjälp av affinitetsprotein. På 90-talet skapades ett nytt sådant protein utvunnet från Protein A på KTH, den så kallade affibodyn. Att arbeta med affibodies är ofta fördelaktigt eftersom de är lätta producera samtidigt som de delar många av de väsentliga egenskaperna hos en antikropp. Affibodies är även kända för att vara mycket stabila, vilket betyder att de i de flesta fall klarar av att vecka sig tillbaka till korrekt struktur efter denaturering. Tyvärr är det inte alltid fallet och ett exempel på det är de affibodies i biblioteket som konstruerats för att binda till spike 1 på SARS-CoV-2 i Johan Rockbergs labb på Proteinteknologi i AlbaNova. I detta projekt har affibodyn ZS1-ORANGE-22, från biblioteket, producerats i tre nya expressionsvektorer som tidigare inte prövats. Vektorerna innehåller olika element som tidigare påvisat öka lösligheten av protein. Resultatet från produktionen visar att vektorn som tidigare använts för produktion av affibodyn producerade den största mängden protein. Däremot uppvisade de tre nya vektorerna som utvärderats i projektet ett större procentuellt utbyte protein efter rening. I kombination med detta har även en studie kring hur buffertars komposition inverkar på proteinlösligheten gjorts. Resultat från denna utvärdering visar att tillsatsen av L-arginin och L-Glutaminsyra till PBS ökar lösligheten av proteinet, men att det även kan en inverkan på dess struktur som gör det mindre lämpligt för tillämpningar samt analys. / Today new drugs based on affinity proteins are constantly developed. In the 90s a new type of affinity protein was discovered from Protein A at KTH, the affibody. Affibodies are often favorable to work with since they are easy to produce and share a lot of essential characteristics with antibodies. They are also known for being stable, meaning they can refold correctly after being denatured. However, this is not always the case and an example of this is the library of affibodies designed to bind to spike 1 on SARS-CoV-2 in Johan Rockbergs lab at Proteintechnology in AlbaNova. In this project the affibody ZS1-ORANGE-22, from said library, has been produced in three new expression vectors which all have elements that previously have shown to help with precipitation. The results show that the vector that has previously been used to produce the affibody produces a larger quantity of protein. However the three new vectors that have been evaluated in this project give a larger percentage yield after purification. In combination with this, a study on how buffer compositions impact protein solubility has been conducted. Results have shown that adding L-Arginine and L-Glutamic acid to a PBS buffer has positively impacted the solubility of the proteins. However, this may also affect their structure making them less suitable for application and analysis.

<p>Proučavane su koroziona postojanost i tendencija lepljenja različitih<br />materijala u kontaktu sa tečnom Al&ndash;Si&ndash;Cu legurom. Ispitivanjem su<br />obuhvaćeni čelik za rad na toplo, plazma nitrirani čelik i dupleks<br />slojevi sa CrN, TiAlN, TiAlSiN i CrAlN prevlakama, različitog nivoa<br />površinske hrapavosti. Za ispitivanja pomenutih fenomena<br />primenjena je metoda izvlačenja, koja je unapređena kako bi se povećale<br />njena tačnost i verodostojnost simulacije procesa livenja. Korozioni<br />efekti su pojačani tako što su uzorci osim kratkog kontakta sa odlivkom<br />zadržavani i u dužim periodima u kontaktu sa tečnom legurom (5 i 20<br />min). Uprkos opštim stavovima, za ispitivane materijale je<br />ustanovljeno da su sile izvlačenja uzoraka iz Al&ndash;Si&ndash;Cu odlivaka<br />nezavisne od njihovog hemijskog sastava. Uticaj hrapavosti je izražen<br />kod uzoraka sa prevlakama kod kojih pri smanjenju hrapavosti dolazi do<br />povećanja sile izvlačenja. Sve ispitane prevlake su sklone mehaničkom<br />lepljenju Al&ndash;Si&ndash;Cu legure za svoje površine, ali sa aspekta korozije u<br />tečnom metalu značajno prevazilaze performanse čelika i plazma<br />nitriranog sloja. Duži kontakt livene legure sa površinama prevlaka<br />uzrokovao je niže vrednosti sila izvlačenja, što je posledica<br />oksidacije površina prevlaka. Ustanovljeno je da su ispitivane<br />prevlake inertne ka tečnoj leguri aluminijuma. Međutim, dolazi do<br />oksidacije i korozije materijala podloge kroz greške rasta koje su<br />prisutne u prevlakama. Stečena znanja o identifikovanim<br />mehanizmima habanja i propadanja zaštitnih slojeva prevlaka<br />poslužiće daljem razvoju dupleks slojeva namenjenih za zaštitu alata<br />za livenje pod pritiskom.</p> / <p>Corrosion resistance and soldering tendency of different materials in molten<br />Al&ndash;Si&ndash;Cu alloy were studied. Hot-working tool steel, plasma nitrided steel and<br />duplex layers with CrN, TiAlN, TiAlSiN and CrAlN top coatings, which were<br />produced to various degree of surface roughness, were covered by the study.<br />An ejection test was employed for investigation of the concerned phenomena.<br />The ejection test was improved in order to increase its accuracy and the<br />reliability of process simulation. Samples were examined in both short and<br />extended periods of contact (5 and 20 min) with liquid casting. Casting<br />solidification was extended in order to intensify the corrosion effects. Contrary<br />to common findings, it was found that the ejection force of the investigated<br />materials does not depend on their chemical composition. For the coated<br />samples, a pronounced dependence of the ejection force on the surface<br />roughness was found. The ejection force increases with decrease in surface<br />roughness. All investigated coatings are prone to mechanical soldering by Al&ndash;<br />Si&ndash;Cu alloy. Still, their corrosion resistance substantially exceeds the corrosion<br />resistance of steel and plasma nitrided layer. Longer exposure of coated<br />samples to cast alloy induced lower ejection forces, which is a consequence<br />of coatings oxidation. It was found that the investigated coatings are inert to<br />liquid aluminium. However, the underlying material undergoes oxidation and<br />corrosion through coating growth defects. The findings concerning the wear<br />mechanisms of protective layers support further development of duplex layers<br />intended for die casting tools protection.</p>